True omental cysts are discovered most frequently in children or young adults. They are generally asymptomatic and detected incidentally at laparotomy or at autopsy. Large cysts may produce a palpable abdominal mass or cause diffuse abdominal swelling. On plain abdominal radiographs and barium studies, omental cysts appear as nonspecific soft tissue masses causing displacement or pressure effects on adjacent bowel loops. Ultrasound or CT shows an omental cyst as a fluid-filled mass that often contains internal septations.
Benign tumors of the omentum are very rare; most are composed of spindle cell elements. Computed tomography can demonstrate the fatty nature of an omental lipoma. On ultrasound, these tumors typically appear as strongly echogenic masses with good sound transmission.
By far the most common tumor of the omentum is metastatic carcinoma. Diffuse neoplastic infiltration of the greater omentum produces the distinctive CT appearance of a soft tissue mass separating the colon or small intestine from the anterior abdominal wall, with obliteration of the normal fat plane in the area. Such “omental cakes” are most frequently produced by metastatic ovarian adenocarcinoma; other causes include metastases frorp cervical, endometrial, and colon carcinoma.omental mass · omental mass abdomen · omental masses ·