[A case of orbital hemangiopericytoma].

A 38-year old woman presented with severe proptosis in the left eye which had been developing for more than ten years. CT scan revealed a large mass in the left orbit, therefore lateral orbitotomy was performed. The histopathology of this tumor consisted of ovoid to spindle-shaped cells tumor around a sinusoidal vascular component forming staghorn channels. This tumor was diagnosed as a hemangiopericytoma. The prognosis of orbital hemangiopericytoma including clinicopathological aspects are discussed with reference to recent reports.