dedifferentiated liposarcoma

dedifferentiated liposarcoma

A poorly-differentiated pleomorphic sarcoma which accounts for 10% of liposarcomas. It is a mixture of well-differentiated liposarcoma and a high-grade non-lipogenic sarcoma, an aggressive component. About 50% of retroperitoneal liposarcomas are dedifferentiated. 75% occur in the retroperitoneum; other sites include the extremities and paratesticular region. Dedifferentiated areas can be that of:
(1) High-grade pleomorphic sarcoma, which mimics what was once called pleomorphic malignant fibrous histiocytoma or fibrosarcoma, or
(2) Low-grade sarcoma, mimicking well-differentiated fibrosarcoma, low-grade myxofibrosarcoma or fibromatosis. Divergent differentiation occurs in 1/4 of cases and includes rhabdomyosarcomatous, leiomyosarcomatous, osteo-chondrosarcomatous or angiosarcomatous areas.

Clinical findings
Legs (e.g., popliteal fossa and medial thigh), retroperitoneal, perirenal, mesenteric region, shoulder.

Prognosis
Despite their high-grade appearance, DDLs tend to be less aggressive than other types of high-grade pleomorphic sarcomas: local recurrence in 40%, metastases in 10%. Location is the single most important prognostic factor; retroperitoneal DDLs fare far worse than those located on the extremities.

DiffDx
Any high-grade or pleomorphic sarcoma should be considered, as well as metastatic poorly-differentiated carcinoma, melanoma, or lymphoma.

Genetics
Ring or giant-marker chromosomes due to an amplification of chromosome 12q13-15, which results in the amplification of one or more genes in the region, including HMGA2, MDM2, SAS, GLI, CHOP, CDK4.
References in periodicals archive ?
Dedifferentiated liposarcoma (DL) most commonly arises de novo, but may also arise within a recurrent WDL.
Dedifferentiated liposarcoma arising in the background of well-differentiated liposarcoma, with MDM2 gene amplification detected on fluorescent in-situ hybridization (FISH) testing.
Among the poster presentations will be clinical results from the Phase 2 portion of the company's Phase 2/3 SEAL study evaluating selinexor, its lead, oral SINE compound, in patients with advanced unresectable dedifferentiated liposarcoma. The remaining posters will highlight data from ongoing investigator-sponsored trials evaluating selinexor in combination with approved anti-cancer agents in hematologic and solid tumor malignancies.
Differential diagnosis of atypical lipomatous tumor/well-differentiated liposarcoma and dedifferentiated liposarcoma: Utility of p16 in combination with MDM2 and CDK4 immunohistochemistry.
Cabillic et al., "Differential diagnosis of atypical lipomatous tumor/well-differentiated liposarcoma and dedifferentiated liposarcoma: utility of p16 in combination with MDM2 and CDK4 immunohistochemistry," Human Pathology, vol.
At the same time, the histopathologic examination of the atrial mass showed a high-grade sarcoma consistent with dedifferentiated liposarcoma. The tissue exhibited spindle cells with pleomorphism, multinucleated giant cells, and inflammatory cells.
Liposarcoma is the most frequent histological subtype, and well-differentiated liposarcoma (WDL) and dedifferentiated liposarcoma (DDL) account for 90% of retroperitoneal liposarcomas [2].
Guillou et al., "MDM2 and CDK4 immunostainings are useful adjuncts in diagnosing well-differentiated and dedifferentiated liposarcoma subtypes: a comparative analysis of 559 soft tissue neoplasms with genetic data," American Journal of Surgical Pathology, vol.
Fletcher, "Dedifferentiated liposarcoma: clinicopathologic analysis of 32 cases suggesting a better prognostic subgroup among pleomorphic sarcomas," The American Journal of Surgical Pathology, vol.
Dedifferentiated liposarcoma with rhabdomyoblastic differentiation in an 8-year-old girl.
Marino-Enriquez, "STAT6 is amplified in a subset of dedifferentiated liposarcoma," Modern Pathology, vol.
Dedifferentiated liposarcoma of the lower extremity with low-grade dedifferentiation and low-grade osteosarcomatous component.