CT detection of intraabdominal disease in patients with lower extremity signs and symptoms.

The initial clinical presentation of intraabdominal disease can be in an extraabdominal location. This phenomenon most commonly occurs in the setting of bowel perforation secondary to diverticulitis, appendicitis, or carcinoma, with resultant spread of infection caudal to the abdomen. Hematomas and pancreatic fluid collections may also dissect out of the abdomen. The spread of these disease processes is likely to occur in a predictable fashion along anatomic tissue planes. Computed tomography (CT) is well suited to demonstrate the extraabdominal site of disease, the pathway of spread from the abdomen, and the occult intraabdominal process. We describe four such cases in which CT was useful and discuss the anatomic pathways involved.