Computed tomography (CT) is a widely accepted modality for the detection, localization, and potential therapeutic drainage of abdominal abscesses. The CT demonstration of extraluminal gas within the abdomen usually signifies the presence of an abscess. We report two cases of nonpurulent spontaneous tissue necrosis which simulated a gas containing abscess on CT. The significance of a gas-containing mass detected by CT must be interpreted cautiously since this appearance is not necessarily pathognomonic of a drainable abscess. Confirmation of purulent material within a suspected abscess collection requires documentation by percutaneous aspiration or surgery.