Ruptured splenic abscess: a cause of pneumoperitoneum in a patient with AIDS.

We encountered a case of pneumoperitoneum caused by a gas-forming splenic abscess in a patient with acquired immunodeficiency syndrome (AIDS). Plain abdominal films and computed tomography demonstrated a large amount of free air. Pneumoperitoneum was eventually shown to represent gas liberated from fermentation by gas-forming organisms within the splenic abscess. Gas-containing necrotic tissue from the ruptured spleen mimicked the spillage of feces from colon perforation. The authors emphasize that a ruptured abscess should be included in the differential diagnosis of acute abdomen in an immunocompromised patient.