extraskeletal myxoid chondrosarcoma

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 is distinctively hypovascular and lacks well-developed hyaline cartilage.
Parachordoma is immunohistochemically and cytogenetically distinct from axial chordoma and extraskeletal myxoid chondrosarcoma.
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].
Bulbous urethra involved in perineal extraskeletal myxoid chondrosarcoma in a child.
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.
Most common diagnosis were GIST and Undifferentiated sarcoma not otherwise specified 7 cases (14%) each, followed by Ewings sarcoma /PNET were 6 cases (12%), Synovial sarcoma were 5 cases (10%), 4 cases (8%) of Liposarcoma & Rhabdomyosarcoma each, 3 cases (6%) of Leiomyosarcoma & Fibrohistiocytic sarcoma each, 2 cases (4%) of Dermatofibrosarcoma protuberance & Malignant peripheral nerve sheath tumour each, Other cases like Neuroblastoma, Extraskeletal Myxoid Chondrosarcoma also identified.
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.
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.
Identification of C11orf95-MKL2, the resulting fusion oncogene of t(11;16)(q13;p13), is useful in establishing the diagnosis of chondroid lipoma, a benign soft tissue tumor that can be mistaken for a sarcoma, especially myxoid liposarcoma or extraskeletal myxoid chondrosarcoma.
For example, EWSR1 is rearranged in ES/PNET, desmoplastic round cell tumor, extraskeletal myxoid chondrosarcoma, some myxoid/round cell sarcomas, and clear cell sarcoma.
3,11,12) The differential diagnostic entities of chordoma include extraskeletal myxoid chondrosarcoma, chondrosarcoma, liposarcoma, metastatic mucinous adenocarcinoma, salivary gland carcinoma (head and neck region), myoepithelial tumors, and metastatic renal cell carcinoma.