International Journal of Surgical Pathology 4(2):115-120, 1996 Hemangiopericytoma of the Ovary

A hemangiopericytoma occurring in the right ovary of a 29-year-old woman is re-ported. Microscopically, the tumor exhibited a solid proliferation of uniform oval to spindled cells with a homogeneous vascular pattern and necrosis. Immunohisto-chemically, the tumor cells were negative for both estrogen receptor and proges-terone receptor. Ultrastructurally, the tumor cells contained a small amount of actin filaments, and were separated by basal lamina or collagen fibers. When making a di-agnosis, it is difficult to distinguish hemangiopericytoma of the ovary from ex-trauterine endometrial stromal sarcoma. In addition to the findings described above, the absence of either pre-existing endometriosis or glandular differentiation in the tumor, along with the immunohistochemical negativity for sex-steroid hormone receptors, indicated the diagnosis of hemangiopericytoma of the ovary. Int J Surg Pathol 4(2):00-00, 1996 Key words: ovary, hemangiopericytoma, sex-steroid hormone receptor, immuno-