Myxoid Chondosarcoma, Extraskeletal
Extraskeletal myxoid chondrosarcoma is defined as a malignant mesenchymal neoplasm of uncertain differentiation, displaying abundant myxoid matrix, a lobulated architecture and cords and strands of uniform cells, characterized by NR4A3 gene rearrangements. The term “chondrosarcoma” was originally chosen based on the positivity for S100, the resemblance to chondroblasts at electron microscopy, and on focal cartilage formation. The latter is however extremely rare, as is the expression of cartilaginous differentiation markers, and it is now generally accepted that the term “chondrosarcoma” in extraskeletal myxoid chondrosarcoma is a misnomer. Therefore, since the 2002 WHO classification, the tumor is classified in the group of “of uncertain differentiation.” With emerging genetics, “NR4A3- rearranged myxoid sarcoma” might be a more appropriate term.
Extraskeletal myxoid chondrosarcoma is rare and represents <1% of all soft tissue sarcomas.
References and Further Reading
- Kohashi, K., Oda, Y., Yamamoto, H., et al. (2008). SMARCB1/INI1 protein expression in round cell soft tissue sarcomas associated with chromosomal translocations involving EWS: A special reference to SMARCB1/INI1 negative variant extraskeletal myxoid chondrosarcoma. The American Journal of Surgical Pathology, 32(8), 1168–1174.CrossRefGoogle Scholar