Orbital mesenchymal chondrosarcoma.

Mesenchymal chondrosarcoma is rare in the extraskeletal system and is even more unusual in the orbit. There is little difficulty making a histologic diagnosis because it consists of islands of well-differentiated cartilage surrounded by undifferentiated mesenchymal cells arranged in a hemangiopericytoma-like pattern (1-5). We have seen two identical cases of orbital mesenchymal chondrosarcoma in the last 2 years, and this article describes the findings on radiography and computed tomography (CT).