Malignant transformation of a testosterone-secreting ovarian steroid cell tumor: a case report.

Background: Ovarian Steroid Cell Tumors (SCT) are rare sex cord-stromal tumors accounting for less than 0.1% of ovarian neoplasms. Most are hormonally active and present with symptoms of androgen excess. Steroid cell tumor, not otherwise specified (SCT-NOS), represents the majority of cases and carries the greatest malignant potential, although most tumors are benign and cured with surgical excision. Malignant transformation of an initially benign SCT-NOS is rarely reported, and the molecular mechanisms underlying progression remain poorly characterized. Case: A 41-year-old woman presented with amenorrhea, acne, and hirsutism with markedly elevated testosterone. Imaging demonstrated an 8-cm predominantly solid right adnexal mass. She underwent laparoscopic right salpingo-oophorectomy, and pathology revealed SCT-NOS without histologic features of malignancy. Testosterone normalized postoperatively, and she was managed with surveillance. Three years later, she presented with dyspnea and abdominal pain; imaging demonstrated pleural effusion, ascites, pelvic masses, and peritoneal carcinomatosis. Cytoreductive surgery confirmed malignant SCT-NOS with nuclear atypia, necrosis, and increased mitotic activity. Despite adjuvant carboplatin, paclitaxel, and bevacizumab followed by maintenance therapy, she developed platinum-resistant progression with peritoneal and nodal disease and is currently receiving additional systemic therapy with poor response. Longitudinal next-generation sequencing demonstrated molecular evolution during disease progression. The recurrent, malignant tumor harbored variants in Conclusion: This case presents a rare ovarian steroid cell tumor, not otherwise specified, initially managed with unilateral salpingo-oophorectomy and surveillance given its benign pathologic features. Three years later, the patient developed malignant recurrence. Despite complete surgical cytoreduction and administration of platinum-based adjuvant chemotherapy, the patient experienced disease progression. This case highlights the potential for malignant transformation in benign-appearing SCT-NOS and underscores the importance of counseling patients on the rare risk of recurrence and the need for novel therapeutic strategies in recurrent disease. Integration of clinical, pathologic, and molecular data may improve risk stratification and management of this rare tumor.