Hemangiopericytoma of the Ovary

Abstract

A hemangiopericytoma occurring in the right ovary of a 29-year-old woman is reported. Microscopically, the tumor exhibited a solid proliferation of uniform oval to spindled cells with a homogeneous vascular pattern and necrosis. Immunohistochemically, the tumor cells were negative for both estrogen receptor and progesterone receptor. Ultrastructurally, the tumor cells contained a small amount of actin filaments, and were separated by basal lamina or collagen fibers. When making a diagnosis, it is difficult to distinguish hemangiopericytoma of the ovary from extrauterine 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.