Appendices epiploicae of the colon: radiologic and pathologic features.

Appendices epiploicae are adipose structures protruding from the serosal surface of the colon. They can be seen with abdominal radiography and cross-sectional imaging if the colonic wall is surrounded by intraperitoneal contrast material, ascites, or blood. Normal appendices epiploicae appear as lobulated masses of pericolic fat, usually 2-5 cm long and 1-2 cm thick. Their enlargement, deformity, or altered radiopacity may result from various pathologic processes that can originate locally or extend from adjacent viscera. In a series of 22 cases, appendices epiploicae were affected by spontaneous torsion and hemorrhagic infarct, calcification due to aseptic fat necrosis, primary or secondary inflammation, enlargement by lipomas or metastases, and incarceration in hernias. Disorders of appendices epiploicae are often manifested by nonspecific clinical signs and symptoms (eg, torsion is often mistaken for appendicitis or diverticulitis). These entities should be included in the differential diagnosis of any unexplained abdominal pain or pericolic lesions in adults.