Poorly differentiated extraskeletal myxoid chondrosarcoma with t(9;22)(q22;q11) translocation presenting initially as a solid variant devoid of myxoid areas.

Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft tissue tumor associated with the translocation t(9;22)(q22;q11-12). Although it has a typical microscopic appearance its morphologic spectrum is wide. We report a case of clinically aggressive, poorly differentiated EMC showing the characteristic translocation, which presented initially as a poorly differentiated sarcoma devoid of myxoid areas in the upper arm of an 85-year-old man. The recurrent tumor contained scattered myxoid areas, which merged imperceptibly with the poorly differentiated areas. Some myxoid areas contained necrotic foci surrounded by viable cells giving rise to a pseudorosette-like arrangement. There were epithelioid foci. This case confirms that solid variants of EMC may exist. Poorly differentiated EMC may have a worse prognosis than classic EMC.