extraskeletal myxoid chondrosarcoma

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extraskeletal myxoid chondrosarcoma

A phenotypically and genotypically distinct mesenchymal malignancy with tumour-specific fusion genes, which affects older adults and represents 2.5% of soft tissue sarcomas. ESMCS differs from the primary skeletal chondrosarcoma given the myxoid changes, and is classified as a tumour of uncertain differentiation. It arises in the deep soft tissues of the leg in 75% of cases (thigh, popliteal fossa and buttock). 80% occur in the proximal extremities and limb girdles; 20% in the trunk.

Extraskeletal myxoid chondrosarcoma
• Cellular variant without myxoid matrix;
• Classical variant;
• Dedifferentiated type;
• Epithelioid type;
• Rhabdoid type;
• Small cell type.

Imaging
Cortical erosion and buttressing.

Epidemiology
Male:female ratio, 2:1.

DiffDx
Intramuscular myxoma, myxoid liposarcoma, fibromyxoid sarcoma, myxoid embryonal rhabdomyosarcoma.
 
Differentiation
Cartilaginous, neuroendocrine, neural.

Management
Surgical excision; adjuvant chemotherapy if nodal spread or metastasis.

Prognosis
Frequent local recurrence; late metastases; 5-year, 10-year, 15-year survival, 90%, 70%, 60% respectively; continued follow-up is necessary.
References in periodicals archive ?
Extraskeletal myxoid chondrosarcoma (EMC) is characterized by the abundant chondromyxoid matrix and small, uniform cells with round to oval nuclei.
Extra skeletal myxoid chondrosarcoma microscopically shows cord like arrangement of esinophilic cells which are smaller in size than chondroid lipoma.
Extraskeletal myxoid chondrosarcoma was identified as a distinct entity for the first time by stout and verner in 1953.
Extraskeletal myxoid chondrosarcoma consists of non-cohesive elongated tumor nests without ductal or tubular structures and the cells are cytokeratin negative [18].
Extraskeletal myxoid chondrosarcoma (EMC) is an uncommon low-grade sarcoma of the soft tissue, usually presenting as a slow-growing mass in men in their fifth to sixth decades.
This method is sensitive yet not specific for ES/PNET because there are other entities that demonstrate EWS gene rearrangement, including desmoplastic small round cell tumor, clear cell sarcoma, extraskeletal myxoid chondrosarcoma, and myxoid liposarcoma.
Myxoid chondrosarcoma of the mastoid bone, A case report with literature review.
64,65) Primary pulmonary myxoid sarcomas bear a striking histologic resemblance to extraskeletal myxoid chondrosarcoma but lack the characteristic translocations of extraskeletal myxoid chondrosarcoma that fuse NR4A3 on chromosome 9q22 to a variety of partner genes.
DIFFERENTIAL DIAGNOSIS: Parachordoma and Myxoid chondrosarcoma can be considered.
191) In a study of 138 tumors, including myxoid liposarcoma and other myxoid neoplasms, some of which may fall into the differential diagnosis, such as extraskeletal myxoid chondrosarcoma, 36 of 38 cases of myxoid liposarcoma (95%) were positive for NY-ESO-1, whereas all other tumor types were negative.
The main differential diagnoses for typical OFMT with bland round cells include epithelioid neurofibroma, epithelioid schwannoma, chondroid syringoma, myxoid chondrosarcoma, and other epithelioid and myxoid mesenchymal tumors.