Pathological Case of the Month

12-YEAR-OLD girl presented to the Pediatrics C linic o f T aipei M unicipal Chung-Hsiao Hospital, Taipei, Taiwan, with several months’ history of abdominal distension and mild dyspnea. Family and medical histories were noncontributory. Abdominal and pelvic examination showed a tender pelvic mass extending into the right costal margin. The other physical findings were insignificant. Ultrasonogram, abdominal x-ray films, and computed tomographic scan (Figure 1) showed a large, partially calcified intraperitoneal mass extending from the pelvis to the xiphoid process. Preoperative serum a-fetoprotein and human chorionic gonadotropin levels were within normal range. During a laparotomy, a large tumor of the right ovary with a capsular tear was found. The omentum and peritoneum were erythematous and finely granular. A right salpingooophorectomy and biopsy of the omental implant were performed. The right ovarian tumor measured 23315315 cm and weighed 1300 g. The capsule was ruptured and the tumor was solid and cystic. Microscopic sections are shown in Figure 2 and Figure 3. Postoperatively, the patient has been healthy with no recurrent disease for 31 months.