A CASE OF PRIMARY TORSION OF THE GREATER OMENTUM

Abstract

An 18-year-old man was referred to the hospital with a suspecion of appendicitis for right lower abdominal pain which lasted from the day before admission. On admission the body temperature was 37.6°C. He had tenderness, muscular defense, and Blumberg sign in the right lower abdomen. On blood analysis the white blood cell count increased to 15, 700/mm3. Abdominal ultrasonography (US) visualized a 2×3cm tumor with a hypoechoic and heterogenous internal and hyperechoic margin directly under the abdominal wall of the right lower quadrant. Laparotomy was performed under a diagnosis of acute appendicitis. No inflammation, however, was seen in the appendix, and primary torsion of the greater omentum in which a portion of the right greater omentum was twisted clockwise by 6 turns was revealed. This disease presents difficulty in preoperative diagnosis and is often diagnosed as acute appendicitis. Among 37 cases of primary torsion of the greater omentum seen in the literature, US or CT was performed only in 7 or 2 cases respectively. US findings in 5 cases in which the tumor was visualized were compared with histologic findings, and the following features can be drawn: US findings of the disease differs according to the degree of venous congestion, hemorrhage, and necrosis of the greater omentum; the disease can be differentiated from appendicitis, if it has a hyperechoic large tumor; and when the tumor mimicking appendicitis is visualized which is unable to be differentiated from appendicitis, CT may be useful.