Large cell variant of small cell carcinoma, hypercalcemic type, of primary peritoneal origin

Background. Large cell variant of small cell carcinoma hypercalcemic type (SCC-HT) is extremely rare. All reported cases involved an ovary, and one with primary peritoneal origin has not been described. Also, convincing neuroendocrine granules have not been illustrated. Case. A 35-year-old woman underwent an exploratory laparotomy for leiomyomas. Intraoperative impression of peritoneal carcinomatosis was confirmed on frozen section. TAH/BSO, debulking/omentectomy followed. The tumor was present on the pelvic/abdominal peritoneum. The normal-sized ovaries were free of tumor grossly. The tumor had features of large cell variant of SCC-HT, described in the ovary. Furthermore, unequivocal neuroendocrine granules were present. The patient received standard chemotherapy for SCC. At 22 months she is NED. Conclusion. SCC-HT should be considered in the differential diagnosis of primary neoplasms of the peritoneum.