Recurrence of Adult Granulosa Cell Tumor in the Greater Omentum 11 Years after Surgery

Adult-type ovarian granulosa cell tumors (AGCTs) are very rare tumors that account for <5% of all ovarian carcinomas. AGCTs have low malignancy potential and rarely metastasize 5–30 years after the initial diagnosis. Because time has passed from the first surgery and because recurrence develops in various locations, the differential diagnosis is difficult. In particular, tumors developing in the greater omentum are encountered rarely, and it is necessary to carefully consider the differential diagnosis, including primary and secondary neoplasms. Although CT is useful to detect omental tumors, the diagnosis requires invasive procedures. We report a case of AGCT recurrence in the greater omentum that was resected during laparoscopic cholecystectomy. A patient visited our hospital with right-sided abdominal pain. The CT revealed gallbladder stones, a ureteral stone, and a right abdominal mass. The diagnosis of the abdominal tumor was difficult on the basis of blood biochemical testing, gastrointestinal endoscopy, or image inspection. Although the patient underwent several previous surgeries and there were no findings of malignancy with positron emission tomography, we chose to resect the tumor for combined diagnosis and treatment during laparoscopic cholecystectomy. Intraoperative findings showed that the tumor originated from the greater omentum, and the tumor was diagnosed as AGCT recurrence by pathology. A recurrence of AGCT in the greater omentum is very rare, and laparoscopic surgery was safe and useful for resection, in our case.