Since 1949, only 52 cases of hemangiopericytoma (HPC) of the nose and paranasal sinuses have been reported in the literature. Of the latter, only 2 originated from the maxillary sinus. This article reports 2 new cases. One arose in the maxillary sinus and involved the pterygopalatine fossa, skull base, and infratemporal fossa. The second tumor was located in the sphenoethmoidal recess. A new combination of techniques for resection of hemangiopericytoma of the skull base is described. Prognostic criteria for such tumors are reviewed, in conjunction with histological diagnosis.