Microcystic Stromal Tumor of the Ovary: A Case Report of a Newly Described Ovarian Neoplasm With a β-catenin (CTNNB1) G34E Mutation.

Microcystic stromal tumor of the ovary (MSTO) is an exceedingly rare, unusual, and recently described entity with unique genetic alterations that assist in its diagnosis. We describe the case of a 50-year-old woman who presented with a complex right ovarian mass. A hysterectomy with bilateral salpingo-oophorectomy was performed and revealed an ovarian mass consistent with MSTO by histomorphology and immunohistochemical studies.