Two cases of primary torsion of the greater omentum were described. The first patient was a 5-year-old boy who was admitted to the hospital because of severe abdominal pain for 1 day. The The clinical features were similar to perforated acute appendicitis. Laparotomy revealed a normal appendix and the greater omentum twisted around its pedicle. The second patient was a 7-year-old girl admitted to the hospital because of abdominal pain in right lower quadrant for 2 days. The clinical features were that of acute appendicitis. Laparotomy revealed a normal appendix and primary torsion of greater omentum around its pedicle. In both cases, resection of twisted omentum and incidental appendectomy were done. The microscopic findings in two cases consisted of congestion and vascular hemorrhage. Both patients recovered uneventfully. Torsion of the greater omentum, therefore, may be added to the entities to consider in the differential diagnosis of acute appendicitis.

Although intraperitoneal teratomas are rare, teratomas of the greater omentuma are seldom reported. A single case of omental teratoma with torsion in a 26-month-old girl is reported. The patient presented with abdominal pain and a palpable mass. Ultrasonography and CT of the abdomen showed a large cystic mass with a non homgenious solid component composed of fat and calcification. The lesion was surgically excised. Pathology revealed a mature omental teratoma. The hospital course was uneventful.

One case of primary omental torsion in a 10 year-old, 43 kg boy is presented. He presented with a history of acute, continuous pain in the upper abdomen, aggravated by changes of position. Physical examination of his abdomen showed board-like rigidity, tenderness and rebound tenderness over the entire abdomen. The preoperative diagnosis was perforated peptic ulcer. Exploratory laparatomy revealed torsion of the greater omentum. The tor sed omentum was excised and the outcome was good. Omental torsion is a rare surgical condition and is difficult to diagnose prior to operation. Therefore, in case of negative exploration for acute abdomen, the omentum should be included among the organs examined. In addition, careful search for an inflammatory focus should be made, because secondary omental torsion with intraabdominal sepsis is much more common than primary torsion.