Primary retroperitoneal myxoid/round cell liposarcoma is a nonexisting disease: an immunohistochemical and molecular biological analysis
Ronald SA de VreezeDaphne de JongIvon H. G. TielenHenrique J. RuijterPetra M. NederlofRick L. HaasFrits van Coevorden
79
Citation
25
Reference
10
Related Paper
Citation Trend
Keywords:
Myxoid liposarcoma
To broaden the knowledge of myxoid morphology in liposarcoma, eight cases of unusual liposarcoma with combined well-differentiated and myxoid malignant fibrous histiocytoma (MFH)–like myxoid areas are reported. The tumors arose as huge retroperitoneal masses in elderly patients, except for one that occurred in the spermatic cord. Three cases had local recurrences, and one of the seven patients who were followed up had died of the tumor. Grossly, the tumors were mostly confluent and multinodular and showed a glistening myxoid appearance in variable proportions, which merged gradually into or were juxtaposed to yellow fatty or sclerotic whitish areas. Microscopically, in addition to areas of well-differentiated lipoma-like or sclerosing liposarcoma, all the tumors contained myxoid portions characterized by scattered multinucleated or bizarre giant cells and a prominent plexiform vascular pattern that resembled myxoid MFH or myxofibrosarcoma. The myxoid areas were associated with discernible lipogenesis. High-grade dedifferentiation was present in one tumor. Cytogenetically, in one case, the myxoid lesion had nonrandom chromosomal aberrations, such as ring and marker chromosomes, characteristic of a well-differentiated variant of liposarcoma. In a nested reverse transcription-polymerase chain reaction analysis using archival paraffin-embedded tissue, it was seen that none of the eight tumors with myxoid MFH-like features had TLS/FUS-CHOP fusion transcripts characteristic of myxoid and round cell liposarcomas. These clinicopathologic and molecular features suggest that the current myxoid tumors are more closely related to well-differentiated liposarcoma rather than to ordinary myxoid liposarcoma despite their unequivocal myxoid morphology. Missense point mutations of the p53 gene were detected in two (25%) cases by single-strand conformation polymorphism and sequence analyses. Immunohistochemical expressions of p53 and mdm2 were observed in 75% of the cases, in which immunoreactive tumor cells were seen more often in the myxoid MFH-like areas. Thus, altered p53 pathways, such as p53 gene mutation and mdm2-mediated inactivation of p53, may play a pathogenetic role in this form of tumor progression showing myxoid MFH-like morphology in liposarcoma, as has been suggested in dedifferentiated liposarcoma.
Myxoid liposarcoma
Cite
Citations (55)
Myxoid liposarcoma
Cite
Citations (10)
Dedifferentiated liposarcoma of the deep soft tissue of the lower extremities is an infrequent finding. Myxoid liposarcoma is considered the most common soft tissue neoplasia arising in this anatomic region. Divergent differentiation usually occurs within well-differentiated liposarcoma and is exceedingly rare in a myxoid liposarcoma. We report a 32-year-old man who developed a dedifferentiated liposarcoma of the thigh on the background of a pre-existing myxoid liposarcoma. The gross examination of the surgical specimen showed a 11/7/2 cm tumour mass with solid tan-grey areas and focal myxoid degeneration. The microscopic examination revealed a malignant lipogenic proliferation, containing round cells with hyperchromatic nuclei and atypical lipoblasts, confined to the basophilic stroma with a myxoid aspect. Abrupt transition towards a hypercellular, non-lipogenic area consisting of highly pleomorphic spindle cells with atypical mitotic figures was also noted. Immunohistochemical staining was performed. Tumour cells in the lipogenic area were intensely positive for S100 and p16, and CD34 staining highlighted an arborizing capillary network. The dedifferentiated tumour areas showed positive MDM2 and CDK4 staining within neoplastic cells, with the Ki 67 proliferation marker expressed in approximately 10% of the cells. Wild-type TP53 protein expression pattern was documented. Thus, the diagnosis of a dedifferentiated liposarcoma was established. This paper aims to provide further knowledge about liposarcomas with divergent differentiation at peculiar locations, emphasizing the importance of histopathologic examination and immunohistochemical analysis for establishing the diagnosis and assessing the therapeutic response and prognosis of this condition.
Myxoid liposarcoma
Myxofibrosarcoma
Basophilic
Cite
Citations (3)
Liposarcomas are separated into clinicopathological entities by a characteristic morphological spectrum and distinctive genetic changes. Myxoid liposarcoma (MLS) represents one such entity with specific chromosomal translocations leading to the generation of fusion genes, the human translocation liposarcoma (TLS)-CCAAT/enhancer binding protein (C/EBP) homologous protein (CHOP) or the Ewing sarcoma (EWS)-CHOP. In the present study, four cases of liposarcoma with detection of TLS-CHOP or EWS-CHOP, whose postoperative diagnosis was other than MLS (one well-differentiated liposarcoma, two de-differentiated liposarcomas and one unclassified) were examined for medical records, imaging data and histopathology. Clinical records demonstrated that three of the four cases were considerably difficult to diagnose definitively, and histopathological re-examination pointed out areas of myxomatous change as a minor component (<10%). Their dominant components (>90%) resembled pleomorphic sarcoma, pleomorphic malignant fibrous histiocytoma and monophasic synovial sarcoma. The current cases may represent an extreme variant of the morphological spectrum within MLS. In cases of difficulty in making definitive diagnosis of soft tissue sarcoma by standard histopathological examination and identification of myxoid stroma even as a minor component, analyzing TLS-CHOP and EWS-CHOP fusion genes may aid the diagnosis of unusual MLS.
Myxoid liposarcoma
Synovial Sarcoma
Histopathology
Fusion transcript
Cite
Citations (8)
Myxoid liposarcoma and Ewing sarcoma are the two most common tumor types that are characterized by the FET (FUS, EWSR1 and TAF15) fusion oncogenes. These FET fusion oncogenes are considered to have the same pathological mechanism. However, the cellular similarities between cells from the different tumor entities remain unknown. Here, we profiled individual myxoid liposarcoma and Ewing sarcoma cells to determine common gene expression signatures. Five cell lines were analyzed, targeting 76 different genes. We employed unsupervised clustering, focusing on self-organizing maps, to identify biologically relevant subpopulations of tumor cells. In addition, we outlined the basic concepts of self-organizing maps. Principal component analysis and a t-distributed stochastic neighbor embedding plot showed gradual differences among all cells. However, we identified five distinct and robust subpopulations using self-organizing maps. Most cells were similar to other cells within the same tumor entity, but four out of five groups contained both myxoid liposarcoma and Ewing sarcoma cells. The major difference between the groups was the overall transcriptional activity, which could be linked to cell cycle regulation. We conclude that self-organizing maps are useful tools to define biologically relevant subpopulations and that myxoid liposarcoma and Ewing sarcoma exhibit cells with similar gene expression signatures.
Myxoid liposarcoma
Cite
Citations (0)
Kaposi sarcoma (KS) is an intermediate vascular sarcoma that can cause significant morbidity and mortality in patients if left untreated. It is associated with human herpesvirus 8 (HHV-8) infection. Definitive diagnosis is supported by classic histopathology including slit-like vascular spaces, spindle cells, lymphocyte infiltration, and extravasated red blood cells on H&E stain and positive immunohistochemical (IHC) staining for HHV-8. We present a challenge we encountered in detecting HHV-8 by IHC in a mucosal lesion demonstrating classic histopathology for KS.
Histopathology
Stain
Infiltration (HVAC)
Kaposi's sarcoma
Cite
Citations (1)
This paper presents the results of an analysis the chimeric genes FUS/CHOP and EWS/CHOP in patients diagnosed as having liposarcoma in order to make a differential diagnosis in both soft tissue tumors and various variants of liposarcoma. Liposarcomas were found in 5 of 7 cases of primary tumors: 4 chimeric transcripts of the FUS/CHOP type (5-2), a variant of alternative splicing of the FUS/CHOP type (5-2) with depletion in 14 p.n. anda rare variant of the EWS/CHOP type (7-2). Fluorescence in situ hybridization (FISH) confirmed translocations in the tumor samples with the chimeric genes being detected. Reverse transcription-polymerase chain reaction and FISH revealed no chimeric genes specific to myxoid sarcoma in a group of patients with other variants of liposarcoma. Thus, the findings support the strict specificity of the chimeric genes FUS/CHOP and EWS/CHOP for myxoid liposarcoma and the expression of these genes in most tumors of this type.
Myxoid liposarcoma
Cite
Citations (0)
Myxoid liposarcoma
Cite
Citations (79)
The diagnosis of MFH depends on the demonstration of histiocytic and fibroblastic functions. MFHs may phagocytose fat; therefore, lipid stains are useless. By electron microscopy, cytoplasmic lipid is membrane-bound. Immunohistochemical staining for vimentin and histiocytic markers may be helpful. Liposarcoma is diagnosed only when there is convincing evidence of synthesis and storage of fat by the tumor cells. By electron microscopy, cytoplasmic lipid is nonmembrane-bound. Both MFH and liposarcoma have subtypes. In MFH, the pleomorphic forms are the most common. Myxoid MFH is less common; all other types are rare. In liposarcoma, the myxoid types are by far the most common. The myxoid types of both MFH and liposarcoma may contain other elements that vary in degree and geographic distribution and that can raise the histologic grade. About 50% of liposarcomas are low-grade tumors; these are almost always purely myxoid. Low-grade myxoid liposarcoma has a much better prognosis than other types. Myxoid liposarcoma has a better prognosis than myxoid MFH. The peak incidence of MFH is in the seventh decade of life whereas that of liposarcoma is in the fifth decade. A substantial number (roughly 25% to 30%) of MFHs occur in the subcutaneous tissue. Clinically they are almost invariably mistaken for ganglion cysts. Liposarcoma, however, is likely to occur in or below the buttocks. Most are in the anterior thigh. Subcutaneous liposarcoma is extremely rare. A tumor in this area is likely to be either a more malignant myxoid MFH or one of the benign atypical lipomatous tumors. In both MFH and liposarcoma, the development of distant lesions is related to the tumor's histologic grade and size and to local recurrence. Favored metastatic sites of MFH are lung and lymph nodes. Favored sites of distant lesions in the myxoid/round cell types of liposarcoma are intra-abdominal, retroperitoneal, other soft-tissue areas (especially in the neck), and bone. Lymph node involvement is very rare. Because myxoid/round cell liposarcomas have a marked propensity to involve intra-abdominal sites, abdominal computed tomography and bone scan are recommended in the initial evaluation and follow-up of high-risk patients (those with high-grade tumors larger than 15 cm and those with local recurrence of intermediate- or high-grade tumors of any size).
Myxoid liposarcoma
Cite
Citations (9)
Myxoid liposarcoma and pleomorphic liposarcoma: cito-histological correlations. A correlative cytologic and histologic study of a myxoid liposarcoma of the shoulder in a 72 year-old man and a pleomorphic liposarcoma observed in the retroperitoneum of a 84 year-old woman, are presented. A preoperative FNAB cytology performed in both cases showed necrotic material containing spindle-stellate shaped cells, interspersed in a myxoid matrix, with rare classical monovacuolated lipoblasts and fragments of plessiform vessels were seen in the first and scattered pleomorphic and multinucleated cells, with prominent nucleoli and numerous atypical mitosis in the second. A malignant mesenchimal spindle-cells tumor, with myxoid matrix and pleomorphic cells, consistent with liposarcoma, respectively were suspected. Gross and histological specimens confirmed the cytological suspect. Authors discuss main cyto-histological differential diagnoses of myxoid tumors, and point out the importance and a correct differentiation between myxoid liposarcoma and intramuscular myxoma. The cytologic appearance of pleomorphic liposarcoma is similar to histologic type and therefore the problem of a differential diagnosis with soft tissue tumors is analogous. When mono or plurivacuolated lipoblasts are absent, differential diagnosis between pleomorphic histiocytoma and liposarcoma is impossible. Nevertheless this is not a important problem at cytological level because both tumors have a had prognosis and must be treated with radical surgery. Definition of correct histologic type will be more suitable on histologic specimens.
Myxoid liposarcoma
Undifferentiated Pleomorphic Sarcoma
Myxofibrosarcoma
Cite
Citations (0)