Small cell carcinoma of the ovary, hypercalcemic type complicated by enterocutaneous fistula: a case report

Background: Small cell carcinoma of the ovary, hypercalcemic type, is a rare, highly aggressive malignancy that predominantly affects young women and is associated with poor prognosis and limited treatment options. Case presentation: We report the first documented case of small cell carcinoma of the ovary, hypercalcemic type, in a 30-year-old Pakistani woman who presented with abdominal pain, vomiting, weight loss, and biochemical evidence of hypercalcemia. Imaging revealed a large left adnexal mass measuring 9.3 cm × 10.7 cm × 9.7 cm. Subsequent histopathological and immunohistochemical analysis demonstrated characteristic features of small cell carcinoma of the ovary, hypercalcemic type with complete loss of SMARCA4 (BRG1) expression, confirming the diagnosis. The patient underwent total abdominal hysterectomy, bilateral salpingo-oophorectomy, and lymph node dissection, followed by multi-agent chemotherapy. Despite her initial response, she developed widespread metastatic disease with tumor infiltration of the abdominal wall and encasement of ileal loops. This ultimately resulted in a contained ileal perforation and the formation of an enterocutaneous fistula—an uncommon and previously unreported complication of small cell carcinoma of the ovary, hypercalcemic type. Conclusion: This case highlights the diagnostic and therapeutic challenges associated with small cell carcinoma of the ovary, hypercalcemic type, and underscores the critical role of SMARCA4 immunohistochemistry in confirming the diagnosis, particularly in resource-limited settings where molecular testing may not be widely accessible.