Sinonasal hemangiopericytomas: clinicopathologic and imaging findings.

Hemangiopericytomas are rare soft-tissue neoplastic lesions that can arise in any part of the body. They are mesenchymal tumors that account for 3 to 5% of all soft-tissue sarcomas and 1% of all vascular tumors. They originate in extravascular cells (pericytes). Some 15 to 30% of all hemangiopericytomas occur in the head and neck; of these, approximately 5% occur in the sinonasal area. We describe our brief retrospective review of 7 histologically proven cases of sinonasal hemangiopericytoma, and we discuss the imaging characteristics and clinical and pathologic findings in these patients.