Malignant Central Nervous System Neoplasms of Mesenchymal Origin

Mesenchymal neoplasms of the central nervous system (CNS), included as mesenchymal nonmeningothelial tumors in the current World Health Organization (WHO) classification of CNS tumors (1), usually arise from the meninges, or from mesenchymal elements of the CNS parenchyma. Their histologic features are those of corresponding extracranial soft-tissue tumors. The most frequent malignant mesenchymal tumors of the CNS are hemangiopericytomas (HPCs) and CNS sarcomas. Benign tumors include chondromas, osteochondromas, osteomas, leiomyomas, rhabdomyomas, and lipomas.