Metastatic Omental Tumor Secondary to Occult Ovarian Serous Adenocarcinoma

Primary tumors within the abdomen frequently spread to the mesentery and omentum, but these deposits may not cause symptoms until they grow large enough to displace organs or cause intestinal obstruction. We present an uncommon case of occult ovarian serous adenocarcinoma presenting as a solitary metastatic omental mass. A 72-year-old female patient found a hard, mobile subcutaneous mass located at the umbilical area. This mass gradually became larger, but there were no symptoms in the gastrointestinal tract. Abdominal ultrasonography showed a homogenous, hypoechoic lesion. A preoperative diagnosis of a huge intra-abdominal lipoma was made, and surgical intervention was carried out. Intraoperatively, we found a tumor mass located in the greater omentum without ascites. The surgical procedure consisted of a complete resection of the omental mass. Frozen section analysis by the pathologist revealed a metastatic serous adenocarcinoma. Intra-abdominal organs including the gastrointestinal tract, ovaries, uterus and pancreas were examined carefully; however, no abnormal lesions were identified either grossly or palpably. Two months after the operation, a computed tomographic scan of the abdomen was performed, and a cystic mass lesion with a 0.9-cm lobulated margin was confirmed in the posterior wall of the right ovary. The patient was then referred to a gynecologist for further survey and underwent another operation. Finally, a pathologic report of the right ovary showed that the primary lesion of this metastatic omental cancer originated from right ovarian cancer. This case demonstrates the possibility of development of a metastatic omental mass from an occult ovarian serous adenocarcinoma.