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What is liposarcoma?

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Liposarcoma is a rare cancer of connective tissues that resemble fat cells under a microscope. It accounts for up to 18% of all soft tissue sarcomas. Liposarcoma can occur in almost any part of the body, but more than half of liposarcoma cases involve the thigh, and up to a third involve the abdominal cavity.

Liposarcoma tends to affects adults between the ages of 40 and 60. When it does occur in children, it is usually during the teenage years.

There are four types of liposarcoma, each with its own unique characteristics and behaviors.

  1. Well-differentiated liposarcoma is the most common subtype and usually starts as a low grade tumor. Low grade tumor cells look much like normal fat cells under the microscope and tend to grow and change slowly.
  2. Myxoid liposarcoma is an intermediate to high grade tumor. Its cells look less normal under the microscope and may have a high grade component.
  3. Pleomorphic liposarcoma is the rarest subtype and is a high grade tumor with cells that look very different from normal cells.
  4. Dedifferentiated liposarcoma occurs when a low grade tumor changes, and the newer cells in the tumor are high grade.

The risk of recurrence and metastasis with liposarcoma increases with higher grade. 

What causes liposarcoma?

Scientists do not yet know the cause of liposarcoma. Although patients sometimes notice a tumor after they experience an injury, liposarcoma is not known to be caused by trauma. It is also not known to develop from benign lipomas, which are harmless lumps of fat.

What are the symptoms of liposarcoma?

Most people with liposarcoma do not feel sick. They might notice a lump (which can be soft or firm to the touch) that is usually painless and slow growing. Unfortunately, tumors in the abdomen can grow to be quite large before they are found.

How is liposarcoma diagnosed?

A physical exam is the first step in the liposarcoma diagnosis process. Lumps that are 5cm or larger and deep-seated, firm and fixed to underlying structures are usually considered suspicious.  Imaging tests are the next step and often include an X-ray and an MRI. An experienced radiologist might suspect the diagnosis based on the results of these tests.

There are two main types of biopsy: a needle and a surgical biopsy. The location, incision and technical aspects of the biopsy can affect a patient’s treatment options and outcome. Therefore, it is essential that the biopsy is planned by a surgeon or radiologist experienced with sarcomas.

The results of the biopsy and imaging studies provide physicians with an idea of the “extent of spread,” or stage, of disease that can be used to create a treatment plan.

How is liposarcoma treated?

Surgery is the treatment for primary liposarcomas that have not yet spread to other organs. In most cases, a surgeon will remove the tumor, along with a wide margin of healthy tissue around the tumor, with the goal of leaving the area free of disease and preventing the tumor from returning. Most tumors of the arms and legs can be successfully removed while sparing the involved limb. Occasionally, in about 5% of cases, an amputation is the best way to completely remove the cancer and restore the patient to a functional life. Complete surgical removal of tumors within the abdomen is difficult, in part because of the difficulty in getting clear margins of normal tissue.

The combination of surgery and radiation therapy has been shown to prevent recurrence at the surgical site in about 85-90% of liposarcoma cases. These results vary depending on the subtype of sarcoma that is involved. Radiation therapy may be used before, during or after surgery to kill tumor cells and reduce the chance of the tumor returning in the same location. Radiation therapy that is given before surgery may be more beneficial, but it can also make it more difficult for surgical wounds to heal.

The role of chemotherapy in the treatment of liposarcoma is not clearly defined, but it may be recommended in certain situations where patients are at high risk of recurrence or already have widespread disease.

Prognosis for patients with liposarcoma

Prognosis statistics are based on the study of groups of liposarcoma patients. These statistics cannot predict the future of an individual patient, but they can be useful in considering the most appropriate treatment and follow-up for a patient.

Liposarcoma prognosis is reported based on disease subtype. Five-year disease specific survival rates (chances of not dying from cancer-related causes) are as follows: 100% in well-differentiated liposarcoma, 88% in myxoid liposarcoma, and 56% in pleomorphic liposarcoma. Ten-year survival rates are 87% in well-differentiated liposarcoma, 76% in myxoid liposarcoma and 39% in pleomorphic liposarcoma. However, the site of disease has a strong effect on prognosis of well-differentiated and de-differentiated liposarcoma. If these liposarcomas arise within the abdomen, complete eradication of the tumor in the long term is less common. This is probably because it is difficult for the surgeon to completely remove tumors in this location. 

How are patients followed after treatment?

Routine follow up will continue throughout the patient’s life. It usually includes a physical examination and imaging studies. An MRI or CT scan of the original tumor location is typical, and a chest x-ray or CT imaging is used to detect metastasis.

Last revision and medical review: 10/2012

By Teresa Bell

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Liposarcoma: A Detailed Review

Introduction

The term "liposarcoma" refers to a spectrum of neoplastic processes ranging from lesions that are essentially benign to those that are malignant, more aggressive, and likely to recur and/or metastasize (spread). Decisions regarding the treatment and aftercare of liposarcomas are guided by the known characteristics and behavior patterns of the various subtypes. While many of the principles governing the evaluation and management of other soft tissue sarcomas certainly apply to liposarcoma, there are many features unique to it that deserve special consideration. Management of these tumors requires a multidisciplinary team approach, and should be rendered in centers experienced in the many facets of care of sarcoma patients.

Background

In relation to other types of cancer, soft tissue sarcomas are relatively rare. Approximately 11,000 new cases of soft tissue sarcoma are diagnosed each year in the United States (ACS 2012) representing about 1% of all newly diagnosed human neoplasms (Lewis 1996). Liposarcoma itself constitutes about 9.8% to 18% of soft tissue sarcomas, its incidence second only to that of Malignant Fibrous Histiocytoma (MFH), (Peterson 2003, Enzinger 1995).

Liposarcoma is a tumor derived from primitive cells that undergo adipose differentiation. It is largely a disease of adults, its incidence peaking between the ages of 40 and 60 years, and it shows a slight predominance toward men (Enzinger 1995). When liposarcomas do occur in the pediatric population, they tend to present in the second decade of life (Coffin 1997). In either event, the deep soft tissues of the extremities, particularly those of the thigh, are the most common location, accounting for more than 50% of liposarcomas (Coffin 1997, Pisters 1996). Its presentation in this location is most commonly that of a slow growing, painless mass. Often these tumors are first noticed after the patient has sustained a minor trauma to the area. Having noted a hard lump that doesn’t go away with time often is what prompts the patient with a sarcoma to first seek medical attention. Unfortunately, since patients with sarcomas don’t initially feel "sick", their diagnosis, and thus their treatment, is often delayed.

Liposarcoma was originally described by R. Virchow in 1857. In 1944, Arthur Purdy Stout wrote "surely, one of the most bizarre and fantastic chapters in the story of oncology is furnished by the tumors of fat-forming cells. The strange way in which they grow, their astounding size…and many other peculiar features ... make them of great interest." [See R. Virchow, "Ein fall von Bosartigen zum Theil in der form des Neurons auftretenden Fettgeschwulsten," Arch A Pathol Anat Phys, 1857, 11: pp 281-288 and "Liposarcoma—the malignant tumor of lipoblasts", A. P. Stout, Annals of Surgery, 1944; 119( 1): pp 86-107.]

One unique feature of liposarcoma is its tendency to occur in visceral spaces, particularly that of the retroperitoneum. Up to 1/3 may occur in this location (Peterson 2003). The presentation of liposarcoma in this scenario may be quite different. While a mass may be appreciated, it tends to be found much later, since the retroperitoneal space can accommodate a much larger change in volume than can the thigh, for instance. Also, obstructive urinary and bowel symptoms may predominate as the mass impinges on these structures. The management of liposarcoma in this location can be particularly difficult.

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A Paradigm for Histology-Specific Multimodality Therapy

Introduction

Soft tissue sarcoma represent less than 1% of all human neoplasms with approximately 7,000 new cases diagnosed in the USA per year.1 Despite sharing a common embryologic origin from mesodermal tissue, these tumors encompass a histologically and anatomically diverse group of neoplasms. Liposarcomas are the most common histologic subtype of soft tissue sarcoma and are subdivided into five well recognized subgroups based on morphology and cytogenetic abnormalities:2

  • Well-differentiated (WD)
  • Myxoid
  • Round cell
  • Pleomorphic
  • Dedifferentiated liposarcoma (DD)

Initiated in 1962, the modern liposarcoma histological classification schema has included the category of well-differentiated liposarcoma. Well-differentiated and dedifferentiated liposarcoma comprise the vast majority (approximately 90%) of liposarcoma subtypes while myxoid, round cell and pleomorphic account for less than 10% of liposarcomas.7

Mesoderm comprises the middle germ cell layer and gives rise to cells that comprise cardiac and skeletal muscle, hematopoitic cells and cells producing bone, cartilage and connective tissue throughout the body. In addition this germ cell layer ultimately gives rise to the cells that make up the genitourinary system.

Retroperitoneal Liposarcoma Figures 1A-1C

Retroperitoneal Liposarcoma
Figures 1A-1C...

The term "ALT" for atypical lipomatous tumor was introduced in 1974.3 The recent World Health Organization classification of soft tissue and bone tumors grouped these lesions into one category, "atypical lipomatous tumor/well differentiated liposarcoma." Well-differentiated (WD) liposarcomas are composed of mature adipocytes with significant variation in cell size and focal nuclear atypia. They typically show scattered atypical stromal cells with hyperchromatic nuclei embedded within mature adipose tissue. Fibrous septae are often present. These divide the tumor into irregular lobules infiltrated by atypical stromal cells, and are a feature especially characteristic of the Sclerosing variant of well-differentiated liposarcoma (Figure 1).4

The term dedifferentiated (DD) liposarcoma was advanced by Evans in 1979 to describe liposarcoma that consists of a combination of atypical lipomatous tumor (ALT) components and also cellular, non-lipogenic sarcomatous areas that have significant mitotic activity.5 Grossly, dedifferentiated liposarcoma has the appearance of multinodular yellow masses representing ALT or WD within which discrete solid areas of dedifferentiated liposarcoma can be appreciated by their distinctive fleshy, tan-gray non-lipomatous appearance. It is unclear whether WD and DD originate from two different cellular clones or if there is a process of progressive evolution from WD to DD. However, it is unequivocally established that DD constitutes a high grade lesion with increased cellularity that is prone to disseminate and is associated with a much worse prognosis than WD which has minimal metastatic potential.6 Many sarcoma centers do not report grade when describing liposarcoma in that WD tumors are generally considered to be low grade where as DD tumors are typically high grade. Moreover, grade is frequently not included in multivariate liposarcoma models that include histologic subtype.7

Liposarcomas of the extremity and trunk enjoy significantly lower rates of local recurrence (10-16%) compared to the rate of local recurrence (43%) from liposarcomas arising within the retroperitoneum.8-10 Liposarcomas arising from within the retroperitoneum typically grow to be quite large before associated symptoms are manifest.

Retroperitoneum: The retroperitoneuma is the anatomical space behind (retro) the abdominal cavity. It has no specific delineating anatomical structures. Organs are retroperitoneal if they only have peritoneum on their anterior side. Retroperitoneal organs: ureter, bladder kidneys, duodenum, colon, pancreas and adrenal glands.

Although different liposarcoma histologic subtypes can be observed in soft tissue sarcomas that arise in the retroperitoneum, histologic subtype per se is usually not incorporated into retroperitoneal disease management strategies. Complete surgical resection is a difficult challenge as these large tumors are often surrounded by a thin fibrous capsule which is frequently indistinguishable from surrounding retroperitoneal adipose tissue. Critical structures in the retroperitoneum can also pose a challenge to resectability. Accordingly, it is often difficult to obtain a margin of normal tissue around the tumor. The importance of complete macroscopic resection is well established and resection of contiguous organs in the hope of decreasing the rate of local failure is a common practice. However, evidence that a more extensive resection impacts survival is very limited. Among the factors that significantly influence clinical outcome, histologic subtype is recognized as an independent predictor of local recurrence (LR), distant metastasis (DM) and disease specific survival (DSS).7

A Treatment Strategy According to DD and WD Histology

At the University of Texas MD Anderson Cancer Center (MDACC) we have adopted a strategy of performing less-aggressive surgery for patients based upon the specific liposarcoma histologic subtype. Tumors without a component of dedifferentiation, referred to as either atypical lipomatous tumors or well-differentiated liposarcoma (WD), are associated with a less aggressive clinical course. WD tumors are characterized by repetitive local recurrence without the potential for metastasis. In contrast, dedifferentiated tumors (DD) also recur at a high rate, but have the potential to metastasize and represent an aggressive clinical phenotype. Accordingly, at MDACC we recognize these tumors as distinct with differing tumor biology and clinical outcome. Utilizing this general strategy for patients with WD tumors has resulted in less aggressive surgery without the addition of chemotherapy or radiotherapy. For patients with retroperitoneal liposarcomas with evidence of dedifferentiation, we adopt a more involved treatment approach that begins with neoadjuvant chemo-radiotherapy followed by aggressive surgical resection. In this review we present the rationale for this approach and discuss our clinical results vis-à-vis those centers that do not alter treatment approaches to retroperitoneal liposarcoma based on histologic subtype.

To date, the largest reported series of retroperitoneal liposarcoma resections is from Memorial Sloan-Kettering Cancer Center (MSKCC). In this experience, completeness of resection significantly impacted clinical outcome: the three year disease specific survival for patients with a margin negative resection was 87% compared with 43% for patients resected with grossly positive margins. In this series and others from the MSKCC group an aggressive surgical approach was applied based on the demonstrated prognostic significance of a complete macroscopic resection.7,10-11 Moreover, retroperitoneal liposarcoma histologic subtype did not influence decisions about neoadjuvant or adjuvant chemotherapy in that none of the patients in this series received such systemic treatment. Unlike extremity liposarcoma where tumor size is known to significantly affect outcome the size of retroperitoneal liposarcomas is typically much larger; in this series the mean tumor maximum dimension was 26 cm. As an indication of aggressive surgical resection, over two-thirds of patients in this series underwent resection of contiguous organs, including nephrectomy. Interestingly, contiguous organ resection was associated with a two fold increased risk of death compared to patients not undergoing contiguous organ resection after adjusting for other prognostic factors (p=0.05).7 In the MSKCC series, the local recurrence rate and rate of distant metastasis was 50% and 11% respectively. On multivariate analysis of prognostic factors associated with local recurrence, distant metastasis, and disease-specific survival, only the presence of contiguous organ resection and the DD histologic subtype were significant adverse factors. It is possible that the patients receiving contiguous organ resection simply had more extensive tumor burden rather than worse biology per se. Underlying tumor biology, rather than extensive surgical resection appears to be more important determinant of clinical outcome. We hypothesize that the histologic subtype of retroperitoneal sarcomas may serve as a surrogate for tumor biology and will affect clinical outcome more than extent of initial resection if a gross total excision is performed.

The MDACC Experience

Taking into account the markedly different biologic behaviors of WD compared to DD, our therapeutic approach at MDACC is tailored to reflect these differences. The treatment strategy for a retroperitoneal liposarcoma patient presenting to the MDACC Sarcoma Center is formulated upon multidisciplinary consensus review prior to initiation of therapy. This approach is in contrast to traditional tumor board review of patients who typically undergo resection and are then considered by the multidisciplinary review panel to determine the utility of adjuvant therapy based on final review of the resected specimen pathology. Our practice is to utilize validated diagnostic imaging criteria and selective image guided biopsy of suspected foci of DD to make a preoperative diagnosis of WD versus DD in patients presenting with retroperitoneal liposarcoma. WD patients generally undergo less aggressive surgery avoiding resection of contiguous organs if possible, while patients with DD are treated with neoadjuvant chemotherapy and radiation therapy followed by aggressive surgical resection.

Using this approach, patients may realize benefits from neoadjuvant therapies that would otherwise not be demonstrable were resection performed as the initial treatment strategy. The major theoretical benefits to neoadjuvant chemotherapy are to identify patients who respond to the systemic therapy as measured by the pathologic response, and to initiate treatment of possible occult metastatic disease at the earliest possible time after diagnosis. These potential advantages are offset by several disadvantages of neoadjuvant therapy, namely that definitive resection is delayed and wound healing may be compromised. However, there is evidence to suggest that response to front line sarcoma chemotherapeutic agents may be dependent on histologic liposarcoma subtype, with DD having greater response rates than WD.12

We have recently reviewed our experience utilizing this approach to patients with retroperitoneal sarcoma, demonstrating that WD patients usually benefit from a less aggressive surgical approach that avoids unnecessarily extensive resection. This strategy was developed based on initial anecdotal observations of the generally indolent clinical behavior of WD tumors in contrast to the metastasis prone phenotype of DD tumors. This approach to WD tumors stands in contrast to our traditional aggressive surgical management of other retroperitoneal histologies. The treatment variables and patient outcomes of the 127 patients presenting with primary or locally recurrent resectable retroperitoneal liposarcomas are depicted in Table 1.

Table 1: Treatment characteristics and outcomes of patients presenting to MDACC with primary and recurrent retroperitoneal based on WD and DD histology
 
Well-differentiated
Dedifferentiated
 
N=54
N=73
Treatment Characteristics
No.
%
No.
%
Neoadjuvant chemotherapy
1
1.7
27
35.1
Neoadjuvant radiation
9
15.5
15
19.7
Gross (RO) Resection
50
86.2
66
85.7
Positive microscopic margins
23
40.4
33
43.4
Multiple contiguous organ resection
27
50
55
75
Patient Outcomes \
Local Recurrence
25
46
52
71
Distant Metastases
2
4
33
45
Median time to recurrence (months)
55.5
13.5
5-year recurrence free survival (RFS)
41.9
7.8
5-year overall survival (OS)
92.1
36.5

The incidence of local recurrence was 46% for WD patients and 71% for DD patients while the incidence of distant metastases was 3.7% for WD and 45.2% for DD patients.13 The median overall survival at 5 years was 92.1% for WD patients and 36.5% for DD patients. On multivariate analysis, presentation status (recurrent vs. primary), multifocal disease, and pelvic location were factors significantly associated with recurrence free survival (RFS). While it is difficult to compare outcomes between published single institutional series, our outcomes are comparable to those reported by the MSKCC group in which treatment decisions are apparently not as influenced by the presence of dedifferentiation. In the MSKCC series the incidence of local recurrence was 31% for WD patients and 83% for DD patients while the incidence of distant metastasis was 1% for WD patients and 30% for DD patients at three years of follow up. The 5-year disease specific survival for tumors with WD histology was 83% compared with 20% for tumors with dedifferentiated histology.7

In our series, the tumor burden as measured by tumor size was comparable between WD and DD tumors with the median size of the tumors measuring 20 cm and 17 cm respectively. Over 65% of the WD tumors measured >15cm compared to 55% of the DD tumors which is similar to the median tumor burden reported in the MSKCC series. Despite the comparable sizes of the WD and DD tumors, our apparently less aggressive surgical approach to WD patients resulted in only 46.6% of the WD patients undergoing resection of contiguous organs whereas over 70% of DD patients in our series underwent contiguous organ resection. Interestingly, we achieved equivalent rates of complete tumor resection while using this organ sparing strategy (WD: 86.2%; DD: 85.7%).16 In the MSKCC series, the incidence of contiguous organ resection was not stratified by histologic subtype, rendering further inter-series comparisons problematic.

Preoperative Diagnosis of WD and DD Retroperitoneal Liposarcoma

The success of this less-aggressive treatment approach requires accurate preoperative determination of WD versus DD retroperitoneal liposarcoma histology. At MDACC we utilize radiographic correlates of dedifferentiation to enhance the likelihood of obtaining informative tissue for diagnosis at the time of the CT scan guided biopsy of suspected DD regions. Since retroperitoneal liposarcomas are frequently large and heterogeneous, a random biopsy specimen retrieved from a limited area within the tumor may be very inaccurate; therefore, other diagnostic tools are also needed as adjuncts to unequivocally establish the DD diagnosis. CT scanning has been particularly useful in helping to identify areas of WD and DD within a given retroperitoneal liposarcoma in that retroperitoneal liposarcomas characteristically have an overall fatty appearance with areas of "streakiness" due to the presence of cellular stromal elements within the tumor.14 As a general paradigm, the more well-differentiated the tumor, the more its imaging appearance will resemble that of adipose tissue, whereas foci of DD have a CT appearance more consistent with that of high grade tumor.

Computed tomography (CT) is a medical imaging method employing tomography. Digital geometry processing is used to generate a three-dimensional image of the inside of an object from a large series of two-dimensional X-ray images taken around a single axis of rotation. The word "tomography" is derived from the Greek tomos (slice) and graphein (to write).

Retroperitoneal Liposarcoma Figure 2

Retroperitoneal Liposarcoma Figure 2...

To establish radiographic markers of DD we examined a series of 78 patients (45 with DD and 33 with WD). Features previously reported as possible discriminators between low and high grade tumors were evaluated. One feature, the presence of focal nodular/water density, was identified as a radiographic surrogate marker for discriminating between the two differing histologies. Focal nodular/water density describes an area of nodularity within the tumor that has a density similar to muscle is depicted in Figure 2.

Forty-four out of 45 patients (97.8%) with postoperative pathologic diagnosis of DD were radiologically identified as DD by the study radiologist based on the presence of focal nodular/water density; however 16 patients with WD were diagnosed as DD based on this imaging criterion. In contrast, all 17 tumors that lacked areas of focal nodular/water density were confirmed to by WD on pathologic analysis of the resected specimen. The positive predictive value (PPV) of focal nodular/water density to predict DD histology therefore was 73.3% while the negative predictive value (NPV) was 100%. Taken together, these data suggest that preoperative CT imaging is very sensitive to detect DD histology based the presence of focal nodular/water density; however, its specificity is relative low. Moreover, as the negative predictive value (NPV) of this marker was 100% it appears that the diagnosis of WD can be based on CT scanning alone.

Predictive Values: The positive predictive value (PPV), or precision rate, is the proportion of patients with positive test results who are correctly diagnosed. It is the most important measure of a diagnostic method as it reflects the probability that a positive test reflects the underlying condition being tested for. Its value does however depend on the prevalence of the disease, which may vary. The negative predictive value (NPV) is the proportion of patients with negative test results who are correctly diagnosed.

In this series 72% of patients had pre-referral CT-guided biopsies and in only 22 cases (28%) a CT guided biopsy was performed at MDACC. All the 17 tumors identified as WD based on preoperative CT imaging criteria and confirmed on postoperative pathologic assessment to be WD were also diagnosed as WD on preoperative biopsy. In such patients a preoperative biopsy may therefore not be needed as the diagnosis of WD can be made by CT imaging criteria alone. Out of the 60 tumors that were radiographically identified as DD based on the presence of focal nodular/water density, preoperative biopsy showed DD in 34 (56.7%) cases and WD in 26 (43.4%). In Thirteen patients out of the 26 cases (50%) diagnosed as WD based on preoperative biopsy were found to be DD on postoperative pathologic assessment. The majority of biopsies performed in this series were obtained prior to evaluation at MDACC. It is unlikely that such pre-referral biopsies were taken from areas within the tumor suspicious for DD. Accordingly, we analyzed the 22 CT guided biopsies performed at MDACC. Twelve were taken from suspicious areas from within the tumor identified by the presence of focal/nodular water density by preoperative CT imaging. Of these, all six biopsies confirmed on final pathology as DD were also identified as DD on preoperative CT-guided biopsy. Conversely, 9 CT-guided biopsies taken from non-suspicious areas (fatty or ground glass opacities) were interpreted as WD and 5, nearly 50%, were diagnosed as DD on final postoperative pathologic assessment.

Taken together, these data suggest that a preoperative CT scan-guided biopsy is highly sensitive and specific for DD when taken from suspicious areas of focal/nodular water density. Our approach to a patient who presents with a retroperitoneal liposarcoma is as follows: CT scan to identify and localize areas of a focal nodular/water density as ascertained by the radiologist; if no focal/nodular water density areas are found the tumor is considered to be WD and a biopsy is unnecessary. If areas of a focal nodular/water density are detected then a CT-guided biopsy of these suspicious areas is needed to differentiate between DD and WD. Patients diagnosed as DD by CT-guided biopsy may therefore be considered for neoadjuvant systemic chemotherapy while WD patients generally undergo less aggressive surgery up-front with an aim to avoid resection of contiguous organs if possible.

Future Studies

Recently, the ability of fluorodeoxyglucose (FDG) PET imaging to assess clinically relevant liposarcoma parameters was evaluated in 54 patients prior to therapy. Sarcomas with the most metabolically active areas may have more aggressive tumor biology. In this study significant differences were found for the maximum standardized uptake value (SUVmax) between histologic subtype; tumor SUVmax was found to be a significant correlate of disease-free survival and time to relapse. The mean tumor SUV max was 2.3 for WD, 4.8 for DD and 5.6 for the pleomorphic histologic subtype. Patients with SUVmax >3.6 had a significantly shorter disease-free survival of 21 months compared with 44 months in patients with a SUVmax <3.6.15 In the future, PET-CT may provide even more accurate assessment of retroperitoneal liposarcoma histological subtype, and this possibility merits prospective evaluation.

Positron emission tomography (PET) is a nuclear medicine imaging technique that produces a three-dimensional image of functional processes in the body. The system detects pairs of gamma-rays emitted indirectly by a positron-emitting radioisotope (tracer), which is introduced into the body on a biologically active molecule. If the biologically active molecule chosen for PET is FDG (a derivative of glucose), the concentrations of tracer imaged then give tissue metabolic activity, in terms of glucose uptake.

In our series, DD patients had a five-year overall survival rate of 36.5% despite an aggressive surgical approach combined with high dose systemic chemotherapy. Clearly novel systemic therapies are needed to treat this and other histologic subtypes that are resistant to current multimodality approaches. The ability to identify and therapeutically exploit a unifying molecular abnormality that is associated with a specific histologic subtype is best exemplified by the dramatic success of imatinib mesylate (Gleevec or STI-571) for gastrointestinal stromal tumors (GISTs). Differential gene, RNA, and protein expression patterns identified by high throughput techniques such as cDNA and miRNA arrays as well as tissue microarray and/or proteomic profiling may offer insight into previously unappreciated sarcomagenesis pathways.

A unique characteristic (and the basis for the definition of dedifferentiated liposarcoma) is the presence of dedifferentiated areas within a sarcoma that consists of predominantly well-differentiated histology. This phenomenon begs the question of whether the dedifferentiated component represents an area of WD that has regressed to resemble an earlier stage of developmental cellular maturation as reflected by a dedifferentiated phenotype. Alternatively, areas of dedifferentiation may represent differing stages of maturity in the original sarcoma progenitor cells, also referred to as mesenchymal stem cells. The latter hypothesis is reminiscent of the accepted progression of leukemogenesis in which a lymphoid stem cell type arrests at differing stages of normal lymphoid stem cell maturation, then acquires potential for the transformed phenotype of a cell type specific leukemia or lymphoma.16

Recently, Matushansky et al. proposed a developmental model of sarcomagenesis to define the differentiation-based classification of liposarcomas.17 Using RNA isolated from human mesenchymal stem cells (hMSC) growing in adipocyte conditioned media, gene expression profiling was performed at predetermined days of hMSC-adipocytic differentiation to identify groups of adipocyte differentiation-specific genes. In parallel, to identify genes specific to the sarcomagenesis process that are not involved in the maturation process, a list of genes differentially expressed between normal fat tissue and each liposarcoma histologic subtype were generated from tumor tissue. Genes corresponding to the stage of normal differentiation were analyzed by comparing the two groups of gene sets.

Mesenchymal Stem Cell (MSC): Mesenchyme is embryonic connective tissue that is derived from the mesoderm and that differentiates into hematopoietic and connective tissue, whereas MSCs do not differentiate into hematopoietic cells. Mesenchymal stem cells are multipotent stem cells that differentiate into a variety of cell types such as: osteoblasts, chondrocytes, myocytes, adipocytes and beta-pancreatic islet cells.

Hierarchical clustering analysis of the adipocyte maturation gene set revealed that dedifferentiated and pleomorphic liposarcomas were associated with early maturation time points, whereas myxoid/round cell and well-differentiated were associated with late time points in a maturation process that more closely resembled that of normal fat. Each tumor subtype was compared to its corresponding normal cell stage of differentiation. Using differential gene expression analysis, two distinct gene sets were identified: genes overexpressed in liposarcomas that mark the stage of differentiation arrest, and a distinct set of genes overexpressed in liposarcomas that are not found in the corresponding stage of differentiation which could be enriched for genes critical to sarcomagenesis.17 In the future it is likely that sarcomas will be classified by their molecular pathologic characteristics that both defines the histologic subtype and are also prognostic of the metastatic phenotype.

Conclusions

In conclusion, the biologic behaviors of well-differentiated and dedifferentiated liposarcomas are significantly different. Using two distinct surgical and multidisciplinary approaches we propose that these tumors may be optimally managed as separate disease entities. We have established radiographic criteria that correlate with the presence of the dedifferentiated retroperitoneal liposarcoma components useful in maximizing the accuracy of pre-therapy image-directed diagnostic biopsy. In the future, the characterization of molecular pathways critical to liposarcomagenesis will hopefully facilitate development of individualized treatment strategies based on specific tumor biology, thereby enhancing multidisciplinary therapy for this challenging group of diseases.

Last revision and medical review: 6/2008

By Kerrington Smith, MD (1,3)
Guy Lahat, MD (1,3)
Raphael Pollock, MD, PhD (1,3)
Dina Lev, MD (2,3)
Departments of Surgical Oncology (1), Cancer Biology (2), and the Sarcoma Research Center (3)
University of Texas MD Anderson Cancer Center in Houston, Texas

References

1. Jemal A, Siegel R, Ward E, et al: Cancer statistics, 2008. CA Cancer J Clin 58:71-96, 2008.

2. Nascimento AF, McMenamin ME, Fletcher CD: Liposarcomas/atypical lipomatous tumors of the oral cavity: a clinicopathologic study of 23 cases. Ann Diagn Pathol 6:83-93, 2002.

3. Kindblom LG, Angervall L, Stener B, et al: Intermuscular and intramuscular lipomas and hibernomas. A clinical, roentgenologic, histologic, and prognostic study of 46 cases. Cancer 33:754-62, 1974.

4. Weiss SW: Lipomatous tumors. Monogr Pathol 38:207-39, 1996.

5. Evans HL, Soule EH, Winkelmann RK: Atypical lipoma, atypical intramuscular lipoma, and well differentiated retroperitoneal liposarcoma: a reappraisal of 30 cases formerly classified as well differentiated liposarcoma. Cancer 43:574-84, 1979.

6. Fabre-Guillevin E, Coindre JM, Somerhausen Nde S, et al: Retroperitoneal liposarcomas: follow-up analysis of dedifferentiation after clinicopathologic reexamination of 86 liposarcomas and malignant fibrous histiocytomas. Cancer 106:2725-33, 2006.

7. Singer S, Antonescu CR, Riedel E, et al: Histologic subtype and margin of resection predict pattern of recurrence and survival for retroperitoneal liposarcoma. Ann Surg 238:358-70; discussion 370-1, 2003.

8. Pisters PW, Harrison LB, Leung DH, et al: Long-term results of a prospective randomized trial of adjuvant brachytherapy in soft tissue sarcoma. J Clin Oncol 14:859-68, 1996.

9. Zagars GK, Goswitz MS, Pollack A: Liposarcoma: outcome and prognostic factors following conservation surgery and radiation therapy. Int J Radiat Oncol Biol Phys 36:311-9, 1996.

10. Linehan DC, Lewis JJ, Leung D, et al: Influence of biologic factors and anatomic site in completely resected liposarcoma. J Clin Oncol 18:1637-43, 2000 11. Lewis JJ, Leung D, Woodruff JM, et al: Retroperitoneal soft-tissue sarcoma: analysis of 500 patients treated and followed at a single institution. Ann Surg 228:355-65, 1998.

12. Jones RL, Fisher C, Al-Muderis O, et al: Differential sensitivity of liposarcoma subtypes to chemotherapy. Eur J Cancer 41:2853-60, 2005.

13. Lahat G, Anaya DA, Wang X, et al: Resectable well-differentiated versus dedifferentiated liposarcomas: two different diseases possibly requiring different treatment approaches. Ann Surg Oncol 15:1585-93, 2008.

14. Thomas JM: Retroperitoneal sarcoma. Br J Surg 94:1057-8, 2007.

15. Brenner W, Eary JF, Hwang W, et al: Risk assessment in liposarcoma patients based on FDG PET imaging. Eur J Nucl Med Mol Imaging 33:1290-5, 2006.

16. Scandura JM: Advances in the molecular genetics of acute leukemia. Curr Oncol Rep 7:323-32, 2005.

17. Matushansky I, Hernando E, Socci ND, et al: A Developmental Model of Sarcomagenesis Defines a Differentiation-Based Classification for Liposarcomas.  Am J Pathol, 2008.


It is worth mentioning that, in addition to the previously described locations, liposarcoma may occur in many other locations. Those occurring in the head and neck represent about 5%, while the upper extremity accounts for 10%. Other unusual locations may include the spermatic cord, peritoneal cavity, axilla, vulva and even the breast. While most liposarcomas are believed to arise de novo, those in the breast may arise from a preexisting cystosarcoma phyllodes (Donegan 1979, Austin 1986). Liposarcomas are not known to arise from benign lipomas.

History and Physical Exam

Figure 1

Figure 1a and 1b: Axial and coronal MR images showing a large...

Most patients with liposarcomas will present to a clinician with complaint of a mass. Often they are painless unless some sort of trauma has occurred. As stated previously, liposarcomas can become quite large, depending on the site of involvement. Their character can be soft and fleshy or notably firm to palpation. This largely depends on how much the tumor resembles mature fat, or how well-differentiated the lesion is. It is important early on to distinguish large benign lipomas from liposarcoma. Factors that tend to suggest malignancy are masses > 5 cm (about 2 inches) in size and lesions that are deep-seated, firm and fixed to underlying structures (Sim 1994). As with the evaluation of any mass, a thorough physical examination is a must, and careful attention should be directed toward the chest, abdomen and pelvis in addition to the extremity of interest.

Figure 2

Figure 2a and 2b: Axial T1 weighted and STIR images of a myxoid...

The Imaging of Liposarcomas

After a careful history and physical exam has been performed, imaging studies are obtained. For extremity lesions, this begins with standard X-Rays (Sim 1994). These will help elucidate whether or not the bone is involved. Next, an MRI is usually obtained, both with and without contrast enhancement. The MRI findings in liposarcoma can be quite distinct, and suggest the diagnosis even before biopsy is performed. This largely depends on how closely the tumor resembles normal fat (i.e. how "well-differentiated" it is); see Figure 1.

Liposarcomas tend to appear well-circumscribed and lobulated on MRI (Arkun 1997). Contrast enhancement depends on the level of differentiation. Little enhancement is noted in well-differentiated liposarcomas, and more is seen with the more aggressive round cell, pleomorphic and dedifferentiated subtypes. Myxoid liposarcoma, an intermediate variant, shows corresponding heterogeneity with regards to contrast enhancement (Arkun 1997). Other findings characteristic of liposarcoma are thick fibrous septae, nodularity and contrast enhancement on fat-suppressed sequences (Peterson 2003). Additionally, foci of hemorrhage and necrosis may be seen; see Figure 2.

Staging and Biopsy of Liposarcoma

Video: Biopsy for Sarcomas

Once a sarcoma is suspected by exam and imaging, staging and biopsy must be performed. This basically helps determine the nature of the lesion and to what extent, if any, the tumor has spread. Imaging of the tumor as described above is a critical part of the staging process. Additionally, since the lungs are the most common site of metastasis, radiography and CT scanning of the chest is routinely undertaken. With liposarcoma, CT of the abdomen is also recommended due to the relatively common involvement of retroperitoneal and visceral spaces. Laboratory studies including CBC, sedimentation rate and chemistries should be obtained. These tests provide insight into the systemic response elicited by the tumor, and provide a baseline by which therapy may be monitored.

Biopsy is critical, as it is the means by which tissue is acquired in order to make a definitive diagnosis. The histology (or the way it looks under the microscope) of the tumor gives the first clues to its behavior. The requisite tissue can be obtained via needle aspiration or through open incisional or excisional biopsy methods. Open techniques constitute surgery and are performed in the operating room. These provide the most tissue for review by the pathologist, however are often not necessary, or even appropriate. Because many soft tissue sarcomas are readily palpable, needle biopsy is often all that is necessary. This is frequently performed by a radiologist under CT guidance. Incisional biopsy sometimes is necessary to attain an adequate sample of tissue. This involves making an incision in the skin, and obtaining some pieces of the tumor for evaluation. Except for the rarest of instances, excisional biopsy (removing the entire tumor as a biopsy) should be avoided with suspected sarcomas as a well-planned, definitive resection after appropriate staging and tissue diagnosis is preferred.

Figure 3

Figure 3: Surgical & Pathological...

Liposarcoma Pathology

Once tissue from a biopsy or resection is obtained, it is examined under the microscope to determine its histology. There are many special kinds of tests that may be run to aid the pathologist in making a diagnosis from the provided specimen. For this reason, biopsy results may take several days or sometimes even weeks to be finalized.

Figura 4

Figure 4a-b: Surgical & Pathological...

The World Health Organization currently recognizes four subtypes of liposarcoma: well-differentiated (or atypical lipoma), myxoid, pleomorphic and dedifferentiated (Christopher 2002). While these categories represent various points on a spectrum of disease, each of these entities displays its own unique character. Table I provides a simplified description of each of the aforementioned subtypes. Also, See Figure 3 and Figure 4.

Table I: Liposarcoma subtypes 
Well-differentiated Includes atypical lipoma 
Most common subtype (50% of liposarcomas) 
Low grade (doesn’t metastasize, but may recur locally) 
Risk of dedifferentiation
Myxoid Intermediate grade 
Includes round-cell variant as its high-grade counterpart 
Most common type in pediatric age group 
Metastatic risk especially in round-cell variant
Pleomorphic Rarest type (5-10% of liposarcomas) 
High grade 
May mimic MFH or even carcinoma or melanoma 
High risk of local recurrence and metastasis
Dedifferentiated High grade sarcoma arising in association with well-differentiated liposarcoma (MFH, fibrosarcoma) 
Most common with retroperitoneal lesions 
Risk of metastasis

Table 1 compiled from Peterson 2003, Dei Tos 2000, Coffin 1997, Enzinger 1995 and Weiss 1992

A number of cytogenetic correlations also have been made with liposarcoma. Well-differentiated liposarcomas have been found to be associated with abnormalities derived from the q13-15 region of chromosome 12 (Rubin 1997). Such abnormalities also are found in dedifferentiated liposarcoma. Perhaps the best characterized genetic association is that found with myxoid liposarcoma. This represents a translocation, or sharing of genetic material between two chromosomes. In myxoid liposarcoma, the translocation is between chromosome 12 and 16. The result is a gene called TLS-CHOP which is an oncogene, or gene that when expressed can lead to the formation of cancer. This particular translocation and its products are found only in myxoid liposarcoma and therefore are diagnostic of this tumor (Rubin 1997).

The online Atlas of Genetics and Cytogenetics in Oncology and Haematology contains a webpage summarizing classification and other information about Liposarcoma. In particular, see the "Bibliography" section of this webpage which contains an extensive set of references. An introduction to DNA, RNA and proteins can be found on the Nobel website. After clicking on the above hyperlink, make sure to read the section "Learn how to navigate in the document" to take full advantage of this tutorial.

Once the tumor has been characterized, the staging is complete and an appropriate course of treatment can be planned. Table II demonstrates the commonly used staging system for bone and soft tissue sarcomas used by Musculoskeletal Oncologists (adapted from Enneking 1980).

Table II: Surgical Staging of Sarcomas
Stage Grade Site
IA Low Intracompartmental (in bone or muscle compartment of origin)
IB Low Extracompartmental
IIA High Intracompartmental
IIB High Extracompartmental
III Any + Mets Any + Mets

Table II adapted from Enneking, 1980.

Figures 5

Figure 5: Intra-operative photo after limb-sparing surgery...

The Treatment of Liposarcoma

Liposarcoma is, like other soft tissue sarcomas, primarily a surgical disease. The main goal of surgery is to remove the tumor entirely and prevent recurrence. This is most reliably achieved with a wide or radical resection; see Table III.

Although amputation historically was the surgical option of choice for these tumors, today most are amenable to limb-sparing surgery. This is due in large part to advances in the understanding of sarcoma behavior, and in principles of radiation therapy. Such advances have led to a decrease in the frequency of amputations for primary soft tissue sarcomas from more than 50% to about 5% (Spiro 1997).

Video: Limb Sparing Surgery

If a limb-sparing procedure is performed however, it must not compromise the main oncologic goal of tumor removal, and should preserve an extremity that serves the patient better than could a post-amputation prosthesis. It is important to note that even with limb-sparing procedures, functional deficits may be encountered. These may vary significantly depending on the size and location of the individual tumor, and are due to the removal of tissues associated with the tumor (i.e. muscles, tendons, nerves, etc). Reconstruction of post resection deficits can in some instances be performed to minimize these effects; see Figure 5.

Table III: Surgical resection 
Intralesional Curettage
Partial tumor removal
Marginal May leave microscopic tumor behind
Wide Remove tumor and surrounding cuff of normal tissue
Radical Remove entire compartment 
Includes amputation

Table III adapted from Enneking 1980.

Radiation Therapy and Chemotherapy for Liposarcoma

Although local control rates of 85-90% have been achieved with combination therapy consisting of surgery and radiation (Spiro 1997), discussion is ongoing as to the timing of radiation, whether it should be given before or after surgery. Preoperative radiation has the advantage of allowing for smaller doses of radiation applied to a smaller field. Additionally, the tumor may actually shrink in size, making the surgery technically more feasible. The downside is that surgical complications, particularly those related to the wound, are increased. Pollack et al (1998) reported wound healing complications in 25% in patients radiated preoperatively versus 6% in those receiving postoperative treatment. It has been suggested that the improved oncologic outcomes and decreased incidence of more permanent late complications justify the use of preoperative radiation despite the increased complication rate (Virkus 2002). The role of chemotherapy in the treatment of liposarcoma also remains controversial, and is best addressed on a case-by-case basis.

What is commonly accepted regarding liposarcoma is that the behavior of a specific tumor is ultimately dependent on its histological subtype (see above). When treated with surgery and perioperative radiation therapy, well-differentiated liposarcomas exhibit a <10% local recurrence rate and a virtually 0% rate of metastasis (Zagars 1996). In contrast, pleomorphic liposarcomas recur in about 1/3 of cases and spread in about 40%. Five and ten year survival rates for patients with liposarcomas have been reported as 100% and 87% for well-differentiated, 88% and 76% for myxoid variants and 56% and 39% in the pleomorphic subtype (Zagars 1996, Chang 1989).

Video: Amputation for Sarcoma

Local recurrence largely depends on margin status at the time of surgery, with margins positive for the presence of tumor conferring a higher recurrence rate (Sadoski 1993) and thus, less satisfactory outcomes (Spiro 1997). In some scenarios, amputation may still be the procedure of choice for a given patient with a sarcoma. While the goal of amputation is removal of the sarcoma, it does not address metastatic disease and is not fully protective against local recurrence. If amputation is required, the patient often will elect to use a post-amputation prosthesis. This depends largely on the level of the amputation. In short, the more native joints the patient is able to safely retain, the better his/her function tends to be. Essential elements of a successful transition to use of a prosthetic limb are the involvement of a knowledgeable prosthetist, a diligent program of hysical therapy including appropriate post-operative stump care and gait training, and most-importantly, a patient that is truly committed to the process.

Surveillance

Once the tumor has been excised and adjuvant therapy completed, continued surveillance is required to promptly detect any evidence of local recurrence or distant metastasis. This typically involves careful physical examination, x-rays of the afflicted limb and serial imaging of the chest and abdomen (usually CT) and pelvis if indicated. Such follow-up is continued in some fashion for the remainder of the patient’s life. If such disease is detected, treatment is rendered accordingly.

An entity which can sometimes occur after radiation therapy is radiation-induced sarcoma. By definition this arises in previously irradiated tissues that were documented to be "normal" prior to radiation (Arlen 1971). They tend to occur at least 2-3 years after treatment, and may appear up to 30 years later. The most common histology is that of malignant fibrous histiocytoma (70%), and is typically high grade (Enzinger 1995). Survival rates of 5-26% have been reported with regards to these tumors (Robinson 1988, Laskin 1988).

Conclusion

The term "liposarcoma" refers to an array of cancerous tumors. The behavior of any liposarcoma is dependent on its histological subtype. The treatment principles, however, are essentially identical to those of other soft tissue sarcomas. Largely, this includes some combination of radiation therapy and surgery, with or without chemotherapy. It is important for the patient to be serially evaluated for any signs of recurrence or metastasis, and any new complaints should be addressed promptly. This is particularly true in the setting of liposarcoma, which may exhibit unusual patterns of spread and recurrence (Vassilopoulos 2001, Linehan 2000, Pearlstone 1999).

Last revision and medical review: 10/2004

By Mark Gebhardt, MD
Frederick W. and Jane M. Ilfield Professor of Orthopedic Surgery
Harvard Medical School
Children's Hospital, Boston
Chief of the Department of Orthopedic Surgery
Beth Israel Deaconess Medical Center

Peter J. Buecker, MD
Fellow, Orthopaedic Oncology
Harvard Combined Orthopaedic Surgery
Boston, MA

Bibliography and Related Works

ACS - What are the key statistics about soft tissue sarcomas? 2012.

Arkun R, Memis A, Akalin T et al. Liposarcoma of soft tissue: MRI findings with pathologic correlation. Skeletal Radiology 1997; 26: pp 167-172.

Arlen M, Higinbotham NL, Huvos AG et al. Radiation-induced sarcoma of bone. Cancer 1971; 28: 1087.

Austin RM, Dupree WB. Liposarcoma of the breast: a clinicopathologic study of 20 cases. Hum Pathol. 1986; 17(9): pp 906-13.

Brennan MF and Lewis JJ eds. Adjuvant Management. In Diagnosis and Management of Soft Tissue Sarcoma. London, 2002, Martin Dunitz, pp 153-183.

Brennan MF and Lewis JJ eds. Clinical and pathologic correlates. In Diagnosis and Management of Soft Tissue Sarcoma. London, 2002, Martin Dunitz, pp 91-140.

Chang HR, Hajdu SI, Collin C et al. The prognostic value of histologic subtypes in primary extremity liposarcoma. Cancer 1989; 64: 1514.

Christopher DM, Unni KK, Mertens F. WHO classification of tumors. Pathology and genetics: tumors of soft tissue and bone. Lyon, France, 2002, IARC Press, pp 35-46.

Coffin CM. Adipose and myxoid tumors. In Pediatric Soft Tissue Tumors: A Clinical, Pathological, and Therapeutic Approach, Coffin CM, Dehner LP and O’Shea PA eds. Baltimore, 1997, Williams and Wilkins, pp 254-276.

Dei Tos AP. Liposarcoma: new entities and evolving concepts. Ann Dian Pathol 2000; 4: pp 252-266.

Donegan WL. Sarcoma of the breast. Major Probl Clin Surg. 1979; 5: pp 504-42.

Enneking WF, Spanier SS, Goodman MA. A system for the surgical staging of musculoskeletal sarcoma. CORR 1980; 153: pp 106-120.

Enzinger FM and Weiss SW eds. General considerations. In Soft Tissue Tumors, Third Edition. St. Louis, 1995, Mosby, pp 1-16.

Enzinger FM and Weiss SW eds. Liposarcoma. In Soft Tissue Tumors, Third Edition. St. Louis, 1995, Mosby, pp 431-66.

Laskin WB, Silverman TA, Enzinger FM. Postradiation soft tissue sarcomas: an analysis of 53 cases. Cancer 1988; 62: 2330.

Layfield LJ ed. Lipomatous Neoplasms. In Cytopathology of Bone and Soft Tissue Tumors. Oxford, 2002, Oxford University Press, pp 71-88.

Lewis JJ, Brennan MF. Soft tissue sarcomas. Curr Probl Surg 1996; 3: pp 817-872.

Linehan DC, Lewis JJ, Leung D, Brennan MF. Influence of biologic factors and anatomic site in completely resected Liposarcoma. Journal of Clinical Oncology 2000; 18(8): pp 1637-1643.

Pearlstone DB, Pisters PWT, Bold RJ et al. Patterns of recurrence in extremity Liposarcoma. Cancer 1999; 85(1): pp 85-92.

Peterson JJ, Kransdorf MJ, Bancroft LW, O’Connor MI. Malignant fatty tumors: classification, clinical course, imaging appearance and treatment. Skeletal Radiology 2003; 32: pp 493-503.

Pisters PWT, Leung DH, Woodruff J et al. Analysis of prognostic factors in 1,041 patients with localized soft tissue sarcomas of the extremities. J Clin Oncol 1996; 14: pp 1679-1689.

Pollack A, Zagars GK, Goswitz MS et al. Preoperative vs. postoperative radiotherapy in the treatment of soft tissue sarcomas: a matter of presentation. Int. J. Radiation Oncology Biol. Phys. 1998; 42(3): pp 563-572.

Robinson E, Neugut AI, Wylie P. Clinical aspects of postirradiation sarcomas. J Natl Cancer Inst 1988; 80: 233.

Rubin BP and Fletcher CDM. The cytogenetics of lipomatous tumours. Histopathology 1997; 30: pp 507-511.

Sadoski C, Suit H, Rosenberg A et al. Preoperative radiation, surgical margin and local control of extremity sarcomas of soft tissues. J Surg Oncol 1993; 52: pp 223-230.

Sim FH, Frassica FJ and Frassica DA. Soft tissue tumors: diagnosis evaluation and management. J Am Acad Orthop Surg 1994; 2: pp 202-211.

Spiro IJ, Gebhardt MC, Jennings C et al. Prognostic factors for local control of sarcomas of the soft tissues managed by radiation and surgery. Seminars in Oncology 1997; 24(5): pp 540-546.

Vassilopoulos PP, Voros DN, Kelessis NG et al. Unusual spread of Liposarcoma. Anticancer Research 2001; 21: 1419-1422.

Virkus WW, Mollabashy A, Reith JD et al. Preoperative radiotherapy in the treatment of soft tissue sarcomas. CORR 2002; 397: pp 177-189.

Weiss SW, Rao VK. Well-differentiated liposarcoma (atypical lipoma) of the deep soft tissues of the extremities, retroperitoneum and miscellaneous sites: a follow-up study of 92 cases with analysis of "dedifferentiation." Am J Surg Pathol 1992; 16: pp 1051-1058.

Zagars GK, Goswitz MS and Pollack A. Liposarcoma: Outcome and prognostic factors following conservation surgery and radiation therapy. Int. J. Radiation Oncology Biol. Phys. 1996; 36(2): pp 311-319.

 

Liposarcoma Stories and Support

Teresa has dealt with liposarcoma five times

Teresa, Liposarcoma Survivor

I have lived so much life between today and my original diagnosis in 2003. Events in my life stand out now, like pictures in pop-up books, and there are so many of them. I have been blessed by others who have shared their stories, I have learned, loved, grown. Life is so rich now. So don’t start to feel sad or discouraged as you read on. Know that each crisis was a platform from which I was able to spring from, up and onto the next step in life. Read Teresa's story.

LaVon has 30 years of experience

LaVon, Liposarcoma Survivor

When I was overwhelmed with fear of losing my life and leaving my family, I would stand in the shower and have a good cry. I called on my faith and strength to remind myself that I had survived this cancer before and I would do it again.

My husband and family were very supportive through all of these experiences. In the beginning, my two grandchildren were very young, and I prayed to stay healthy long enough to see them grown. I did and I was blessed to see five great grandbabies. I remained what I thought was symptom free and had a good life for 20 years, and I plan to have many more! Read LaVon's story.

Will you share your story?

We would like to fill this page with personal stories that offer hope and encouragement to everyone learning about liposarcoma. Please consider sharing your story.

The words of a liposarcoma survivor, Destrie

It was 10 years ago and I was 35 years old. I was recovering from liposarcoma surgery (a radical muscle excision) and as I lie in bed, I heard a sound that I had heard many times before, but this time it sounded so different. You see, for years I had been waking up to the sounds of the birds next to my bedroom window and was irritated each and every morning that they had awakened me with so much noise. There were always two really loud birds singing to each other.

This time, when I awoke, I actually was able to stop and listen to the song that they had been singing to each other so many mornings before. This time, I stopped and I really listened. I realized how blessed I was to be alive and to be able to hear them that morning. My life had been so hurried before I was touched with cancer. I was busy with my job, my teenage daughter and my husband. Now I truly understand what it means when someone tells you to stop and smell the roses along the way. From that morning on, I awake to the beautiful sounds of the two birds singing their songs to each other and realize how blessed I am to be alive. I am so thankful for those two birds every morning. I still continue to listen to the birds sing each and every day of my life.

"For a moment, my world stopped," from Darrin

I was in the hospital to do radiation for Liposarcoma in my left thigh. I had already had surgery to remove the tumor and things were looking good. Before they started the chemo, my doctor decided to send me for a CT scan just to make sure everything was still okay. After the scan the doctor returned to my room and immediately I knew something was wrong.

As it turned out my cancer had showed up in my left lung, three more tumors. For a moment my world stopped and I thought "well this is it." My wife thought the same, I think, although she never said a negative word. Without her strength I would not have been able to make through that day. Luckily the chemo has worked and it looks like I will be around for quite some time, God willing. We thought that I would have to have lung surgery but as it turned out the tumors have shrunk to such small sizes that the surgeon said he would not put me through surgery to get them, hoping the chemo will completely destroy them. I have one more treatment left before we do more CT scans and I pray every day that it will be the last.

"It is humbling to be back in the arms that raised you," from Irene

My mother, Marina, survived colon cancer in 2001. Since then, she suffers from a variety of health issues and has maintained her generous and loving nature. Mum volunteers for her church, helps to run a folk dancing group (cooking and sewing costumes on many nights) and makes time to babysit her first great grandchild weekly.

My myxoid liposarcoma diagnosis in October 2009 hurt Mum more than her own could have; it tested her faith and resolve. And yet at no time was any of it too much. At every step of the way she has been there: to drive me to appointments at all hours of the day, to sit with me in countless waiting rooms, to patiently wait while I was poked and prodded and radiated and then operated upon, to cook and clean and worry, to fetch and carry, and to be my hands when I couldn’t even wash or feed myself. None of it was too much. With Mum it never is or could be, and I admire the strength and love it takes to do what she does each and every day.

As an adult it is humbling to be back in the arms that raised you and to see with the eyes of the adult not the child. There are many hard and challenging times since diagnosis to treatment and then living day by day, week by week, month by month waiting to be NED…and moments of humor and personal growth become important. I recall being showered with plastic bags over arm and leg wounds, crouching down so that Mum could climb up on the bath tub so she could reach and then Mum laughing: "It was so much easier when you were born!" For all of that and so much more, Mum is my hero.

Dave shares what he's learned

If my sarcoma journey has taught me anything, I’ve learned to cherish the good times, enjoy my family and friends, have a few laughs, and even appreciate a fine meal. I refuse to dwell on the negative or live in fear. Yes, I concede that I am not in control of my destiny, but I am steadfast in my resolve to enjoy life and be thankful for all of the "easy times" that come my way (like now). I no longer grapple with questions that cannot be answered, but instead take things one day at a time.

A moment in Robert's life

While I was receiving post-op radiation treatments for the liposarcoma resected from my thigh, I got to know a woman who was there for breast cancer radiation. For that month we always greeted each other in the morning in the waiting room before heading off for treatment. Months later I ran into her in, of all places, a fitness center. I just thought it was funny that two people who met at one of the grimmest medical places possible would meet again while working out after recovering.

The Online Liposarcoma Support Group at ACOR

The ACOR liposarcoma group has been an invaluable source of support for me. Anyone can join the group, and topics of discussion include medical centers and doctors, treatment options, test results, side effects of treatment, medical insurance and drug trials. Online I am able to honestly express my frustrations and fears that I don't want to burden my family with. In a support group I am able to talk with people who have been through similar experiences, which gives me confidence in my own treatment choices, tips to make the cancer journey easier and a feeling of not being alone.

Connect on Facebook

Here are a few of our favorite Facebook groups that provide opportunities to exchange messages with liposarcoma patients, survivors and their loved-ones.

Find Treatment and Support Resources

We maintain listings of sarcoma treatment centers, local support groups and organizations that provide financial assistance to sarcoma patients and their loved-ones.

Liposarcoma Cancer Research

Help us fund groundbreaking research!

Donate Now

To target your donation to liposarcoma research and/or dedicate it to someone, click on the blue "dedicate this donation" link located to the left of the large "proceed" button.

Financial Accountability

The Liddy Shriver Sarcoma Initiative is pleased to support liposarcoma research and has awarded $600,000 in liposarcoma research grants. Liposarcomas are a complex group of diseases that usually affect adults. They are often resistant to both local treatments (such as radiation therapy) and systemic treatments (such as chemotherapy). It is our hope that research will lead to newer and better treatments for those who are diagnosed with liposarcoma.

The following research studies have been funded by the Initiative after sarcoma experts agreed that they were clinically relevant and scientifically sound:

A "Bedside to Bench" Investigational Platform for Studying Myxoid Liposarcoma

A “Bedside to Bench” Investigational Platform for the Study of Myxoid Liposarcoma$250,000 Grant: With this International Collaborative Grant, researchers from three countries have joined forces to gain new insights into myxoid liposarcoma and its treatment. The investigators will create the world’s largest collection of primary tumor samples and cell models of myxoid liposarcoma, a resource that will be made available to qualified researchers worldwide. They will then use tissue samples to better understand the disease and its response to various treatments. They will also work to identify pathways that can be targeted with existing and experimental drugs.

This grant was funded by the Liddy Shriver Sarcoma Initiative in April 2012. It was made possible by the dedicated and inspirational Landes family, creators of the Wendy Walk.

Translational Research in Well-Differentiated and Dedifferentiated Liposarcoma

Translational Research in Well-Differentiated and De-Differentiated Liposarcoma$250,000 Grant: With this International Collaborative Grant, investigators aim to development of a coordinated program of translational research focused on well-differentiated and dedifferentiated liposarcoma. Investigators will map the epigenetic and genetic landscape of these tumors, model and analyze the evolution of drug resistance and the process of dedifferentiation common to liposarcoma, and develop useful preclinical animal models of liposarcoma.

This grant was funded by the Liddy Shriver Sarcoma Initiative in December 2010. It was made possible by generous donations from the family and friends of Wendy Landes and by a generous donation from Dr. Laura Somerville. Both Wendy and Laura are currently fighting liposarcoma.

High Throughput miRNA Expression Profiling for Liposarcoma

PEDF: a potential therapeutic agent for osteosarcoma$50,000 Grant: In this study, researchers at the University of Texas M. D. Anderson Cancer Center and Stanford University School of Medicine sought to identify subtype-specific, differentially expressed miRNAs that are involved in LPS progression. Future studies will aim to demonstrate the potential of the identified miRNAs as diagnostic markers or perhaps even new therapeutic targets for LPS.

This grant was funded by the Liddy Shriver Sarcoma Initiative in August 2008. It was made possible by a generous gift from the Keating family in honor of James Keating and by a generous gift from Dr. Laura Somerville.

Telomere Maintenance Mechanisms in Liposarcomas

Telomere Maintenance Mechanisms in Liposarcomas$50,000 Grant: In this study, researchers at Memorial University Medical Center characterized liposarcomas with respect to histological subtype and telomere maintenance mechanism. Surprisingly, they were unable to identify an expression pattern that differentiated the tumors based on telomere maintenance mechanism. The researchers plan to continue their work using new knowledge they have gained since the study was proposed.

This grant was funded by the Liddy Shriver Sarcoma Initiative in October 2008. The grant was made possible, in part, by a generous gift from Dr. Laura Somerville. The grant was dedicated to Rose Burt, a courageous, inspirational, and tireless advocate for sarcoma.

Study of Tissue Samples in Conjunction with a Phase II Trial of Dasatinib

$25,000 Grant: This tissue study was performed in conjunction with a clinical trial on several types of sarcoma, including liposarcoma.


  • Figure 1a: Axial and coronal MR images
    Figure 1a: Axial and coronal MR images showing a large but relatively homogeneous, well-defined lesion in the left groin/thigh of a 20 year old male. This lobular appearance is characteristic of large benign lipomas and well-differentiated liposarcomas.
  • Figure 1b: Axial and coronal MR images
    Figure 1b: Axial and coronal MR images showing a large but relatively homogeneous, well-defined lesion in the left groin/thigh of a 20 year old male. This lobular appearance is characteristic of large benign lipomas and well-differentiated liposarcomas.
  • Figure 2a: Axial T1 weighted and STIR images of a myxoid liposarcoma
    Figure 2a: Axial T1 weighted and STIR images of a myxoid liposarcoma in the posterior compartment of the thigh of a 41 year old woman. This lesion appears heterogeneous and does not resemble the intensity of the surrounding subcutaneous fat. Also notable is the significant amount of associated edema. These findings are highly suggestive of malignancy.
  • Figure 2b: Axial T1 weighted and STIR images of a myxoid liposarcoma
    Figure 2b: Axial T1 weighted and STIR images of a myxoid liposarcoma in the posterior compartment of the thigh of a 41 year old woman. This lesion appears heterogeneous and does not resemble the intensity of the surrounding subcutaneous fat. Also notable is the significant amount of associated edema. These findings are highly suggestive of malignancy.
  • Figure 3a: Surgical specimen of a well-differentiated liposarcoma
    Figure 3a: Surgical specimen of a well-differentiated liposarcoma (images shown in Figure 1). The appearance is similar to that of mature fat.
  • Figure 3b: Microscopically, ‘signet-ring’ type cells resembling normal adipose tissue are seen.
    Figures 3b and 3c: Microscopically, ‘signet-ring’ type cells resembling normal adipose tissue are seen. Lipoblasts closely associated with spindle cells (typical of sarcomas) are appreciated at higher power.
  • Figure 3c: and 3c: Microscopically, ‘signet-ring’ type cells resembling normal adipose tissue are seen.
    Figure 3c: Microscopically, ‘signet-ring’ type cells resembling normal adipose tissue are seen. Lipoblasts closely associated with spindle cells (typical of sarcomas) are appreciated at higher power.
  • Figure 4a: Cut gross specimen of a myxoid liposarcoma.
    Figure 4a: Cut gross specimen of a myxoid liposarcoma. While there are areas resembling fat, thick fibrous septae and heterogeneous tissue suggest a more aggressive process than that seen in Figure 3.
  • Figure 4b: Histologically, areas of high-grade tumor are noted by a high degree of cellularity.
    Figure 4b: Histologically, areas of high-grade tumor are noted by a high degree of cellularity, nuclear atypia and mitotic figures. Compared to well-differentiated liposarcoma, few ‘signet-ring’ type cells are seen.
  • Figure 5: Intra-operative photo after limb-sparing surgery.
    Figure 5: Intra-operative photo after limb-sparing surgery for a large liposarcoma. Proximity to major nerves (center of picture) can make wide margins difficult to achieve. Often, preoperative radiation and/or chemotherapy is given in hopes that the tumor will shrink away from major nerves and blood vessels to make limb-sparing surgery more feasible without compromising the ultimate oncologic goal.
  • Retroperitoneal Liposarcoma Figures 1A-1C
    Figure 1: A.) Conventional retroperitoneal liposarcoma WD histology with mature fat and occasional enlarged atypical nuclei. B). Highly cellular nonlipogenic DD with adjacent WD. C.) Characteristic appearance of DD with markedly different size and shaped nuclei and increased spindle cell morphology.
  • Retroperitoneal Liposarcoma Figure 2
    A CT-scan with representative focal nodular/water density representing DD liposarcoma with adjacent WD tumor.