Microcystic stromal tumor

Definition

A rare benign ovarian stromal tumor characterized by a stromal neoplasm with variable microcystic morphology, low mitotic activity, and diffuse nuclear beta-catenin and cyclin D1 immunoreactivity, while inhibin and calretinin are not expressed. Patients most commonly present with symptoms of a unilateral pelvic mass. Hormonal manifestations are usually absent. The tumor may be associated with familial adenomatous polyposis.