A case of glomangiopericytoma involving the orbital wall.

Sinonasal type hemangiopericytomas are very rare tumors, and are often called glomangiopericytoma. They are believed to be derived from perivascular modified smooth muscle cells. Their origin is similar to glomus tumors but some distinct differences exist. Glomangiopericytomas are indolent tumors and overall survival rates are higher after complete surgical excision. Recurrence rates are as high as 30%. We present a case of glomangiopericytoma which involves the orbital wall, noteworthy because such bone-dissolving glomangiopericytomas are extremely rare.