Extraskeletal myxoid chondrosarcoma (EMC) is a rare low-grade malignant mesenchymal neoplasm of the soft tissues, that differs from other sarcomas by unique histology and characteristic chromosomal translocations.
[1] EMC was firstly described in 1953 by Stout et al. when they discussed the different species of extraskeletal chondrosarcoma,[2] but EMC concept was firstly proposed in 1972 by Enzinger et al.[3] Brody thought that this was a unique low-grade malignancy with a low growth rate and both clinically and histopathologically distinct anamnesis beside the typical chondrosarcomas.
[5] Recent statistics demonstrate that EMC shows a higher incidence of local recurrence, metastasis and patient mortality[6] and therefore are classified as mean-grade malignancies.
[7] Two-thirds of EMC tumors are primarily found in sub-fascia soft tissues of the proximal extremities and limb girdles, especially the thigh and popliteal fossa.
NR4A3 is an orphan nuclear receptor that is able to activate the FOS promoter and plays a role in the regulation of hematopoietic growth and differentiation.
TFG is also observed as a fusion transcript with ALK (2p23) in anaplastic large-cell lymphoma and with ANTRK1 (1q21) in some of the thyroid papillary carcinomas.
Smears contain plump spindle-shaped or oval tumor cells arranged in a lacelike pattern of loosely cohesive cords and nests.
Nuclear clefts and grooves are common and the cytoplasm is homogeneous, scanty to moderately abundant, and often appears wispy and tapered, with well-defined borders of cells.
[14] As with all these subgroups of sarcomas, standard treatment for primary EMC is complete surgical resection, in high risk cases followed by radiation therapy.