Signet-ring stromal tumor of the ovary: report of a case and review of the literature.

Signet-ring stromal tumor of the ovary is extremely rare, with only ten cases reported in the literature. We report on a case of signet-ring stromal tumor of the left ovary in a 54-year-old woman who presented with abdominal discomfort. Histologically, the tumor was composed of an admixture of spindle and round cells which contained a large cytoplasmic vacuole which displaced the nucleus, creating a signet-ring appearance. Numerous cells showed intracytoplasmic hyaline globules. Immunohistochemically, the tumor cells showed positivity for vimentin, actin, inhibin, and calretinin, thus confirming the ovarian stromal origin of the neoplasm. The patient remains free of disease one year and 9 months after surgery. Signet-ring tumor of the ovary is a rare variant of benign ovarian stromal neoplasm and should be distinguished from metastatic mucin-secreting signet-ring adenocarcinoma.