Well-differentiated and dedifferentiated liposarcomas with prominent myxoid stroma: analysis of 56 cases.

[dedifferentiated liposarcoma]

Occasional cases of well-differentiated and dedifferentiated liposarcoma (LPS ) contain myxoid stroma , leading to confusion with other sarcomas . The aim of this study was to analyse the clinicopathological and genetic features of well-differentiated /dedifferentiated LPS with prominent myxoid stroma . Fifty -six cases of LPS (22 well-differentiated ; 34 dedifferentiated ) with prominent myxoid stroma were evaluated . Most arose in the retroperitoneum , abdominal cavity , or spermatic cord . The mean size was 170 mm . Myxoid LPS-like plexiform vessels were conspicuous in 11 cases of well-differentiated LPS . In 22 cases of dedifferentiated LPS , myxofibrosarcoma -like curvilinear vessels were prominent . In other cases , the myxoid component had variably bland or pleomorphic morphology . By immunohistochemistry , staining for MDM 2 was positive in 95 % of cases , and CDK 4 in 78 %. Cytogenetics in 13 cases showed ring and giant marker chromosomes . Fluorescence in -situ hybridization showed amplification of 12 q 13 -15 in six cases evaluated . Of 30 patients with follow-up , all but one had local recurrences (up to four ), but only one has so far had distant metastases . Well-differentiated /dedifferentiated LPS with prominent myxoid stroma can closely resemble other sarcoma types , especially myxoid LPS and myxofibrosarcoma . The clinical presentation (large retroperitoneal or abdominal tumour ) is a clue to the correct diagnosis ; the degree of nuclear atypia helps to exclude myxoid LPS . Immunohistochemistry for MDM 2 and CDK 4 and genetic analysis can be useful to confirm the diagnosis .

Diseases
Validation

Diseases presenting "giant marker chromosomes" symptom

dedifferentiated liposarcoma

liposarcoma

pleomorphic liposarcoma

well-differentiated liposarcoma

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