A rare case of small cell carcinoma of the ovary, hypercalcemic type – Diagnostic and therapeutic challenges

Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT), also known as small cell Müllerian ovarian cancer, is a rare and aggressive cancer that primarily affects young women. It contributes to less than 0.1 % of all ovarian cancers and is associated with hypercalcemia in two-thirds of patients. This case report describes a 40-year-old patient presenting with shortness of breath who was ultimately diagnosed with SCCOHT. Laboratory studies demonstrated hypercalcemia and imaging revealed bilateral pulmonary emboli, a mass in the uterus and left adnexa, and peritoneal carcinomatosis. Biopsy revealed a poorly differentiated carcinoma and genetic testing further revealed SMARCA4 mutations, which are seen in cases of SCCOHT. She also had germline ATM and FANCC heterozygous mutations, there is no clear relation established between these mutations and SCCOHT in the literature so far, it would be interesting to see if these mutations can increase the risk of development of SCCOHT and the role of genetic counseling in such cases. Due to its rarity, there is no standard treatment protocol for SCCOHT. She was started on carboplatin/paclitaxel and was referred to a gynecologic oncologist for possible cytoreductive surgery. Reporting such rare cases not only adds to the existing literature but also highlights the importance of further research and the need for defined management guidelines. • Rare and Aggressive Tumor: Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is an extremely rare malignancy, contributing to less than 0.1 % of all ovarian cancers, predominantly affecting young women. • Diagnostic Challenges: The presence of hypercalcemia, SMARCA4 mutations, and the unusual combination of germline ATM and FANCC mutations presented a complex diagnostic scenario, emphasizing the need for thorough genetic evaluation. • Therapeutic Approach: The patient was treated with carboplatin/paclitaxel and referred for potential cytoreductive surgery, underlining the need for individualized treatment strategies due to the lack of standardized protocols for SCCOHT. • Clinical Significance: This case underscores the necessity of reporting rare cancers to enhance understanding, drive research, and support the development of management guidelines for SCCOHT.