Mesenchymal Chondrosarcoma arising in the Central Nervous System: A Diagnostic Pitfall

Abstract

Mesenchymal chondrosarcoma is a rare aggressive neoplasm affecting the bones of young adults. It also arises extraskeletal in CNS, soft tissue and other organs. Intracranial and those that originate from the dura mater are very rare. These tumors constitute an entirely different entity from classical chondrosarcoma. These are characterized by a bimorphic histological pattern composed of highly undifferentiated small round to oval cells and islands of well-differentiated hyaline cartilage with calcification and ossification. We hereby report a case of mesenchymal chondrosarcoma arising from the right tentorium cerebelli in a 40-year-old man with symptoms of mass effect. Histological examination demonstrated sheets of round to oval cells with islands of hyaline cartilage. The diagnosis of mesenchymal chondrosarcoma was made after a thorough microscopic assessment. Tumor in addition to cellular component also revealed a prominent cartilaginous component. We hereby discuss the morphological features of mesenchymal chondrosarcoma arising in the CNS, the differential diagnoses of small round-cell tumors within the CNS, and the differentiating features of mesenchymal chondrosarcoma from the other differential diagnoses.