Lipomatous hemangiopericytoma (adipocytic variant of solitary fibrous tumor) of the orbit. A case report with review of the literature.

Hemangiopericytoma (HPC) of the orbit is a rare tumor presenting with slowly progressive proptosis, ocular motility impairment and visual loss. In 1995, a newly variant of HPC termed lipomatous hemangiopericytoma (LHPC), was described. Only two cases arising in the orbit have been previously reported. The authors describe another case of orbital LHPC and discuss the clinicopathologic features, including the immunohistochemical staining profile and ultrastructural appearance of this distinctive tumor, and briefly discuss the relationship between HPC and solitary fibrous tumor of soft tissue, a neoplasm with many clinical and pathologic similarities.