Adult‐Onset Juvenile Granulosa Cell Tumor With Early Metastasis: A Rare Case With Fatal Outcome

Background Juvenile granulosa cell tumors (JGCTs) are rare ovarian sex cord–stromal tumors that primarily affect children and adolescents. Their occurrence in adults is exceptionally uncommon and presents unique diagnostic and therapeutic challenges due to limited evidence. Case Presentation We report the case of a 25‐year‐old woman who presented with chronic pelvic pain and a large abdominopelvic mass. Imaging revealed a bilobed, heterogeneous ovarian tumor with both solid and cystic components. Surgical resection confirmed a JGCT with aggressive histopathological features, including a high mitotic index and areas of necrosis. The patient underwent radical surgery followed by adjuvant chemotherapy with the BEP (bleomycin, etoposide, and cisplatin) regimen. Despite this, she developed early locoregional recurrence within 6 months, with widespread peritoneal and visceral metastases. Salvage palliative chemotherapy was unsuccessful, and the patient died within weeks due to rapid disease progression. Conclusion This case highlights the potential for unexpectedly aggressive behavior and poor response to standard treatment in adult‐onset JGCTs, which contrasts with the typically favorable prognosis in pediatric cases. It underscores the need for early diagnosis, vigilant surveillance, and the exploration of novel therapeutic strategies. Fatal outcomes in adult patients, though rare, emphasize the importance of reconsidering current management approaches for advanced‐stage disease.