Mixed sex cord–stromal tumor (gynandroblastoma) with malignant morphology involving both ovaries: a case report

Mixed sex cord–stromal tumors, which consist of poorly differentiated Sertoli cells and Leydig cells and juvenile granulosa cell tumor tissue, are extremely rare. Most of these tumors are unilateral and stage I at the time of diagnosis; nonetheless, according to the available relevant English-language literature, these tumors maintain a malignant potential. We herein report a case involving a 15-year-old girl diagnosed with a mixed sex cord–stromal tumor (gynandroblastoma with juvenile granulosa cell tumor component). Left salpingo-oophorectomy was initially performed, and the diagnosis of a juvenile granulosa cell tumor was established. Right salpingo-oophorectomy was performed 1 year later, at which time the specimen showed a different growth pattern involving epithelioid cells and tubules, resembling a Sertoli–Leydig cell tumor. Immunohistochemical staining was performed and the specimen was compared with that obtained 1 year earlier. We concluded that the tumors were linked and most likely constituted a gynandroblastoma (mixed form of sex cord–stromal tumor). Although this is an extremely uncommon ovarian tumor, it should be considered when diverse tumor morphology is identified. Bilateral metachronous involvement of the ovaries is possible. The grade of the Sertoli–Leydig cell component may influence the prognosis of such a tumor.