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PubMed1994

Perineal xanthogranulomatous pseudotumor due to intermittent catheterization: a liposarcoma mimic. Case report.

A large perineal fatty tissue mass shown to be an encapsulated xanthogranulomatous reaction was found in a spinal cord injured man whose neuropathic bladder was for a long time being managed by clean intermittent catheterization, but who had chronic urinary tract infection. He was also known to be a chronic alcoholic. We would say that an alcohol numbed sensorium and multiple catheterizations led to recurrent small urethral perforations which in the setting of chronic bacteriuria promoted the unusual inflammatory mass. Appreciating the increasing use of clean intermittent catheterization for the spinal cord injured, we suspect that similar cases of 'xanthogranulomatous pseudotumors' will be found, and therefore we describe this most unusual clinical presentation.

Granuloma↗
PubMed1996

Lipomatous tumors.

Lipomatous tumors are a common group of mesenchymal lesions. Over the years the major changes in the classification of lipomatous tumors have included the addition of several new variants of lipoma, the use of the term atypical lipoma for well differentiated liposarcoma of the subcutaneous tissue, and recognition of the entity dedifferentiated liposarcoma. Lipomas, the most common lipomatous tumor, account for nearly one-half of all benign lesions. In their typical form they seldom present diagnostic problems for the pathologist. However, lipomas occurring in deep locations (e.g., intramuscular lipoma, perineural lipoma) or those having unusual features (e.g., chondroid lipoma, lipoma with hibernoma, cellular angiolipoma, spindle cell/pleomorphic lipoma) may be confused with liposarcoma. Recent cytogenetic studies have reaffirmed the separate nature of many of the variants of lipoma. Solitary lipomas commonly have rearrangements of chromosome 12, a finding not encountered in multiple lipomas or in spindle cell/ pleomorphic lipoma. Liposarcoma is the most common adult soft tissue sarcoma. It seldom arises from subcutaneous tissues or from preexisting lipomas, and is seldom found in children. The hallmark of liposarcoma is the immature fat cell or lipoblast. Diagnostic lipoblasts have an eccentric, hyperchromatic nucleus, which is indented or scalloped by the presence of one or more fat vacuoles. It is important that these cells occur in the appropriate histologic background because similar cells can be seen in a variety of nonlipomatous lesions (e.g., silicone reaction). Failure to apply strict criteria in identifying such cells and in noting the milieu in which they occur can lead to overdiagnosis of liposarcoma. Liposarcomas are divided into several subtypes: well differentiated, myxoid, round cell, pleomorphic, and dedifferentiated. Liposarcomas can be conceptualized as occurring in two broad groups, myxoid/round cell liposarcoma and well differentiated/dedifferentiated liposarcoma. Myxoid/round cell liposarcomas occur in middle-aged adults primarily as an extremity lesion. Tumors range from pure myxoid (low grade) to pure round cell (high-grade lesions) with some cases having transitional features. Behavior can be related to the amount of round cell areas. A consistent chromosome abnormality t(12;16) characterizes this spectrum of lesions. Well differentiated/dedifferentiated liposarcomas, in contrast, occur in late adult life as extremity or retroperitoneal lesions. They consist of mature fat interlaced with atypical hyperchromatic cells and rare lipoblasts. These lesions recur commonly, but they do not metastasize. Their behavior is strongly influenced by location, with retroperitoneal lesions having the worse prognosis. As a long-term complication of the disease, these lesions may progress histologically (dedifferentiate), a phenomenon that confers upon them metastatic potential. Dedifferentiation is largely a time-dependent phenomenon that occurs in sites in which there is a high likelihood for clinical persistence of disease (e.g., the retroperitoneum). Dedifferentiated liposarcomas occur in an age group similar to well differentiated liposarcoma, but are found far more commonly in the retroperitoneum. Most occur as de novo lesions, with only a small percentage occurring as a late complication of well differentiated liposarcoma, as described above. They consist of well differentiated areas associated with nonlipogenic sarcoma usually resembling high-grade malignant fibrous histiocytoma or fibrosarcoma. However, the range of histologic features occurring in the dedifferentiated areas is more varied than previously appreciated. Low-grade areas resembling fibromatosis or low-grade fibrosarcoma may be seen as the sole expression of dedifferentiation or may co-exist with high-grade sarcoma. (ABSTRACT TRUNCATED)

Adult↗
PubMed1987

Atypical and malignant neoplasms showing lipomatous differentiation. A study of 111 cases.

One-hundred-eleven cases of histopathologically atypical or malignant lipomatous lesions in the somatic soft tissue and retroperitoneum were studied. These consisted of 48 differentiated fatty neoplasms of the somatic soft tissues (DFT-S), 21 fatty neoplasms of the retroperitoneum (DFT-R), 33 myxoid liposarcomas from various sites and nine pleomorphic liposarcomas. DFT-S were defined as lipomatous lesions composed of mature fat and containing atypical stromal cells or lipoblasts. In the somatic soft tissues, this group included lesions that would be classified using published criteria as "atypical lipoma", "pleomorphic lipoma", "well-differentiated lipoma-like liposarcoma", and "sclerosing liposarcoma". All of the DFT-R met previously published criteria for "well differentiated liposarcoma" or "sclerosing liposarcoma". We found no consistent histologic differences between the DFT-S and DRT-R. No pure "round cell" liposarcomas were encountered although many myxoid liposarcomas had "round cell" areas. Follow-up data were available in 80 cases (72%) with a mean follow-up period of over 7 years. Among the DFT-S there were no uncontrollable recurrences, distant metastases, or tumor-related deaths. The depth of the neoplasm correlated with the tendency for local recurrence; no neoplasms primary in the subcutis recurred; 29% of the tumors recurred when they originated in the deep soft tissues or within the muscle. None of the recurrent tumors demonstrated "dedifferentiation." DFT-R had a recurrence rate of 67% and, although there were no distant metastases, nine patients (43%) died of tumor. Five retroperitoneal tumors dedifferentiated but did not metastasize. In light of this experience, we believe that the term "atypical lipoma" is warranted for the DFT-S and "well differentiated liposarcoma" is an appropriate label for the DFT-R. The overall mean survival for the 52 cases of liposarcoma (excluding DFT-S) was 13.6 years. The mean survival in "well differentiated liposarcoma" (11.25 years) was between that for myxoid liposarcoma (16.25 years) and that for pleomorphic liposarcoma (7 years). Six patients (29%) with myxoid liposarcoma developed local recurrences and 6 patients (29%) developed distant metastases and died. Metastasis was always associated with a round cell (or pleomorphic) component with increased numbers of mitotic figures in either the primary tumor or a local recurrence.

Adolescent↗
PubMedDate not supplied

Cytomorphology of lipomatous tumors of soft tissue.

OBJECTIVE: To evaluate the cytomorphologic features of benign and malignant lipomatous tumors of soft tissue on fine needle aspirates (FNA) and determine if the variants of liposarcoma could be identified. STUDY DESIGN: FNA of histologically documented benign (51 cases) and malignant (39 cases) lipomatous tumors were reviewed. Twenty-six of the 51 FNA from lipomas and 34 of the 39 FNA from malignant lipomatous tumors were satisfactory for evaluation. RESULTS: FNA from 26 cases of lipomas were cellular, with lobulated, fibroadipose tissue. Thin and thick capillaries were seen in 92% and 65% of cases, though a chicken wire vascular pattern was seen in only 4 cases (15%). A cytodiagnosis of liposarcoma could be made in 23 cases (88%), and these could be further subtyped into well-differentiated (4 cases), myxoid (8), pleomorphic (4), round cell (3) and liposarcoma, ?type (4). Only 50% of the well-differentiated liposarcomas, 3 of the 10 pleomorphic liposarcomas and 8 of the 17 myxoid liposarcomas were diagnosed as such on FNA. Cytologic diagnosis of the remaining 9 cases of myxoid liposarcoma were pleomorphic liposarcoma (1); liposarcoma, ?type (3); malignant mesenchymal tumor (1); suspicious for malignancy (2); and benign (2). There were no false positives, but there were 3 false negative cases (1 well-differentiated and 2 myxoid liposarcoma). CONCLUSION: Lipomas can be diagnosed readily. Arborizing vessels can be seen in lipomas and should be interpreted with caution. Subclassification of liposarcomas on FNA is possible but not very reliable. Myxoid liposarcomas pose a problem, and aspirates from them can mimic a wide range of morphologic subtypes. The role of FNA in identification of variants of liposarcoma is limited.

Adipocytes↗
PubMed1997

Immunoreactivity for the human hematopoietic progenitor cell antigen (CD34) in lipomatous tumors.

The human hematopoietic progenitor cell antigen (CD34) recently was shown to react with a variety of nonhematopoietic tissues and their tumors, including vascular endothelium, dendritic interstitial fibroblastic cells, and endoneurial cells as well as with the neoplastic cells in a variety of mesenchymal neoplasms of unknown etiology, such as Kaposi's sarcoma, dermatofibrosarcoma protuberans, epithelioid sarcoma, gastrointestinal stromal tumors, and solitary fibrous tumors. Additionally, it has been claimed that normal adipocytes may also react with this antibody. We studied a series of 90 lipomatous lesions to examine the pattern of immunoreactivity of the CD34 antigen in adipose tissue neoplasms. The study included 14 lipomas, 19 angiolipomas, 4 atypical lipomas, 18 spindle cell lipomas, 3 renal angiomyolipomas, 1 intramuscular lipoma, and 31 liposarcomas. Immunostains identified a network of CD34+ spindle cells admixed with the adipose tissue elements in all cases of lipoma, angiolipoma, angiomyolipoma, intramuscular lipoma, and well-differentiated lipoma-like liposarcoma. Additionally, the spindle cell component in all cases of spindle cell lipoma were strongly positive for this antigen. Atypical, stellate spindle cells and multinucleated "floret" cells in all cases of atypical lipoma as well as in six of 12 cases of well-differentiated lipoma-like liposarcoma of deep soft tissue were also positive for CD34. Scattered spindle cells in all cases of myxoid liposarcoma and in one case of round cell liposarcoma, as well as the sarcomatous component in one case of "dedifferentiated" liposarcoma, were strongly positive for this antigen. The round cells in myxoid liposarcoma and round cell liposarcoma, the signet-ring and multivacuolated lipoblasts in well-differentiated liposarcoma, and the pleomorphic atypical cells in pleomorphic liposarcoma were uniformly negative. The results of this study appear to indicate that lipomatous tumors may harbor a population of CD34+ interstitial dendritic spindle cells. Overgrowth or clonal expansion of this dendritic cell subpopulation may account for the development of spindle cell lipomas and for the spindle cell component in some cases of "dedifferentiated" liposarcoma.

Antigens, CD34↗
PubMed2004

[From cytogenetics to cytogenomics of adipose tissue tumors: 2. Malignant adipose tissue tumors].

Malignant adipose tissue tumors, also called liposarcomas, are the most common sarcoma of adult life. They may be hard to distinguish from benign adipose tissue tumors as well as from other types of sarcomas. Well-differentiated liposarcomas and myxoid liposarcomas are the two histological subtypes that have been best characterized at the genetic level. The defining genetic features of well-differentiated liposarcoma cells are supernumerary circular ("ring") and giant linear rod chromosomes. These rings and giant chromosomes contain amplification of the 12q14-15 region, including the MDM2 gene, associated with coamplification of various other chromosomal regions. In addition, they most often lack alpha-satellite centromeric sequences. The detection of MDM2 amplification is a valuable tool for the differential diagnosis between well-differentiated liposarcomas and lipomas. Dedifferentiated liposarcomas usually present with patterns of MDM2 amplification similar to those observed in well-differentiated liposarcomas. In addition, recent CGH-array studies suggest that co-amplification of MDM2 with the 6q23-25 region might be a specific feature. Myxoid and round-cell liposarcomas are characterized by a translocation t(12;16)(q13;p11) that fuses the DDIT3 and FUS genes. A rare variant translocation t(12;22) that fuses DDIT3 with EWS has also been described. The genetics of pleomorphic liposarcoma is still obscure. Pleomorphic liposarcomas show complex karyotypes with many numerical and structural chromosomal aberrations. To date, no specific molecular abnormality has been identified.

Chromosomes, Human, Pair 12↗
PubMed1987

Aspiration cytology of lipomatous tumors: a 10-year experience at an orthopedic oncology center.

The cytodiagnoses of preoperative fine-needle aspirate smears from 72 histologically proven lipomatous tumors (52 lipomas and 20 liposarcomas of varying type) collected during the 10-yr period 1972-1981 were correlated to the corresponding histopathologic diagnoses. Three out of 52 lipomas were erroneously diagnosed as low-grade malignant liposarcomas, and one out of 20 liposarcomas was falsely diagnosed as a benign soft-tissue tumor. Of the 20 liposarcomas, 15 were cytologically diagnosed as such, and the majority of the myxoid and the pleomorphic liposarcomas were correctly diagnosed as to type. Important differential diagnostic problems were, on one hand, the separation of lipoma with regressive changes and histiocytic reaction and lipoma with chondroid metaplasia from low-grade malignant liposarcoma and, on the other hand, liposarcoma from intramuscular myxoma, myxofibrosarcoma, and malignant fibrous histiocytoma. The differential diagnosis of liposarcoma as opposed to other soft-tissue sarcomas is discussed, and it is concluded that preoperative fine-needle aspiration of lipomatous tumors is of value in the management of these tumors.

Biopsy, Needle↗
PubMed2001

Leptin and leptin receptor mRNA are widely expressed in tumors of adipocytic differentiation.

Adipose tissue is the principal source of leptin, a cytokine-like peptide with many biologic functions. Leptin binds to the leptin receptor, present in the hypothalamus and in many other tissues, and modulates energy balance and maintenance of body weight. The expression of leptin and leptin receptor in tumors of adipocytic differentiation has not been previously examined. Because normal adipose tissue is the principal source of leptin and expresses leptin receptor, we hypothesized that tumors of adipose tissue differentiation may also express leptin and/or the long functional form of the leptin receptor (OB-Rb). Leptin and OB-Rb were analyzed by immunohistochemistry, in situ hybridization, RT-PCR, and western blotting in 21 lipomas, 2 hibernomas, and 16 liposarcomas. Immunostaining and in situ hybridization showed leptin and OB-Rb mRNA expression in all cases of lipomas, hibernomas, and liposarcomas, including dedifferentiated and pleomorphic liposarcomas. RT-PCR analysis showed leptin and OB-Rb mRNA in both lipomas (n = 5) and liposarcomas (n = 5). Western blotting identified the 16 kDa leptin protein in a lipoma and a liposarcoma. No important difference in the expression of leptin and OB-Rb mRNA was found between lipomas and liposarcomas, although the level of leptin protein was higher in a lipoma than a liposarcoma by western blotting. These results show for the first time that leptin and OB-Rb mRNA are expressed in lipomas, hibernomas, and liposarcomas. The presence of leptin and its receptor may provide new insights into the pathobiology of these tumors.

Adult↗
PubMed2007

Atypical lipomatous tumor, its variants, and its combined forms: a study of 61 cases, with a minimum follow-up of 10 years.

Sixty-one cases of neoplasms composed wholly or in part of atypical lipomatous tumor were reviewed. Minimum follow-up was 10 years. The cases were divided into 4 groups based on the findings in the initial excision specimen: conventional atypical lipomatous tumor (n=15), cellular atypical lipomatous tumor (n=21), dedifferentiated liposarcoma (n=24), and atypical lipomatous tumor with a pleomorphic liposarcoma-like component (n=1). The term "cellular atypical lipomatous tumor" was applied to atypical lipomatous tumors having areas of increased cellularity that when non-lipogenic lacked the 5 mitotic figures per 10 high-power fields (maximal rate) required for a dedifferentiated component and when lipogenic fell short of being truly pleomorphic liposarcoma-like. Myxoid regions within this spectrum sometimes had prominent or even plexiform vascularity, creating a resemblance to myxoid liposarcoma especially when interspersed small fat cells were present. The most important prognostic factor was tumor location, as none of the 12 patients with a subcutaneous or intramuscular neoplasm died of tumor. Among the 49 patients with neoplasms of central body sites (mostly retroperitoneum), those with dedifferentiated liposarcoma had significantly shorter survival (median 77 mo) than those with cellular (median 142 mo) or conventional (median 209 mo) atypical lipomatous tumor, whereas there was no statistically significant difference between the latter 2 categories. Patients with atypical lipomatous tumor (either cellular or conventional) in central body sites had significantly shorter survival if the tumor transformed into dedifferentiated liposarcoma in recurrence, and, conversely, those with central body site dedifferentiated liposarcoma had significantly longer survival if it recurred as atypical lipomatous tumor. Metastasis (7 cases) occurred only when the initial specimen or a recurrence demonstrated dedifferentiated liposarcoma.

Adult↗
PubMedDate not supplied

[Tumors of the adipose tissue during 10 years of diagnostic activities (1979-1988)].

Adipose tissue tumors in ten years of diagnostic activity (1979-1988). We have reconsidered our material on tumors of adipose tissue, which were observed for 10 years, from 1979 to 1988, at Istituto di Anatomia Patologica dell'Università degli Studi - Arcispedale S. Anna di Ferrara. The whole collection consists of 772 tumors, 742 lipomas and 30 liposarcomas. We have intended to examine the development of our diagnostic experience through time and compare our data with those of literature. Simple lipomas and fibrolipomas are the most common histological types (78.8%), followed by angiolipomas (3.6%) and intramuscular lipomas (2.5%). The other types have a lower percentage. In every cases the morphologic and clinicopathologic features are shown, as well as compared with those of literature, and discordances that may result are interpreted. We are firmly convinced that routine diagnosis is not always compatible with rigid classifications and that it is not easy to use morphologic criteria which vary in quality and quantity. We have consequently aimed at reducing any possible distortion in diagnosis due to subjectivity, by sticking rigorously to consolidated morphology. Although our findings mostly agree with those of literature, some discordances still exist; the most significant of them regard age incidence. Among spindle cell lipomas there are two cases diagnosed in early childhood; the number of angiolipomas as well seems to be very high in this period of life. Particularly important from the clinical point of view has been the decision of diagnosing a thigh tumor as lipoblastoma in an eighteen-year-old boy. Other discordances seem to us less significant, as, for example, the absence of intramuscular lipomas in the thigh, which is to be considered, in our opinion, a chance event that we could not explain otherwise. Liposarcomas represent the 4% of the cases. Only one cases has been diagnosed in a patient less than 40 years old. The location sites agree with those recorded in literature. Our material, on the other hand, does not confirm that the average age of the patients with retroperitoneum liposarcomas is higher than that of the patients with thigh tumors. We has well have identified a greater incidence of retroperitoneum tumors on women. Gross and microscopic findings correspond to those known. Myxoid and pleomorphic liposarcomas are the most common histological types. As regards myxoid liposarcomas, we point out a tumor in the breast in a forty-nine-year-old women. Three of the well differentiated liposarcomas are fibrosing liposarcomas of the spermatic cord. The liposarcomas recurring during the time considered have been seven.(ABSTRACT TRUNCATED AT 400 WORDS)

Adipose Tissue↗
PubMed2003

Elevated telomerase activity, c-MYC-, and hTERT mRNA expression: association with tumour progression in malignant lipomatous tumours.

The role of telomerase activity in tumour progression of liposarcomas is not well understood. Therefore, we investigated 72 liposarcomas of different histological subtypes for an association between telomeric lengths and telomerase activity, and assessed the association between the catalytic subunit human telomerase reverse transcriptase (hTERT) and its activator c-MYC. Telomeric repeat fragment lengths were determined using radioactive DNA-fingerprint analysis with the telomere-specific probe (TTAGGG)(3), whereas telomerase activity was ascertained using the non-radioactive TRAP-assay. To evaluate the expression of hTERT and c-MYC, we applied real-time RT-PCR using a LightCycler. Eight tumours were investigated by microdissection. The MIB1-proliferation index and hTERT and c-MYC protein expression were determined immunohistochemically. Genetic alterations showed a high degree of tumour specificity. Highly malignant myxoid/round cell liposarcomas showed the longest telomeres, the strongest telomerase activity, and the highest hTERT and c-MYC expression levels compared with the pure myxoid variants (p < 0.001), which are of low malignancy. Pleomorphic liposarcoma was characterized by zero or low hTERT and c-MYC expression and telomerase activity, but long telomeres, underlining their different pathogenetic pathway. Elevated gene expression was accompanied by protein immunopositivity. MIB1-proliferation index did not correlate with other molecular markers. We conclude that hTERT and c-MYC expression are associated with telomerase activity in liposarcomas. Elevated hTERT and c-MYC expression as well as high telomerase activity play a role in the tumour progression of this sarcoma type. Nevertheless, each histological subtype of liposarcomas is defined by a specific molecular pattern. Telomerase activation is the most common pathway in liposarcomas maintaining telomeric length.

Biomarkers, Tumor↗