A 46-year old woman presented to our hospital with abdominal pain, diarrhea and bloody stools. She had no previous clinical history of asthma, diabetes, connective tissue diseases, endoscopic examinations and surgery. Laboratory and abdominal ultrasound examination revealed no abnormalities. Barium enema disclosed multiple round filling defects with smooth margins in the sigmoid and descending colon. Further colonoscopy evaluation showed multiple sessile soft, polypoid lesions with normal overlying mucosa. The results of histopathological examination were nonspecific and inconclusive. The patient underwent multidetector computer tomography (MDCT) examination in order to determine the nature and extent of detected polypoid lesions. Multiplanar reformation images with a lung window setting (Figure 1) showed numerous air filled cysts within the wall of sigmoid and ascending colon. Virtual CT colonoscopy (Figure 2) also revealed multiple gas cysts. MDCT findings were consistent with the diagnosis of pneumatosis cystoides intestinalis (PCI). Pneumatosis cystoides intestinalis is a rare condition characterized by multiple air filled cysts within submucosa or subserosa of the intestinal wall. The etiology of PCI is still unclear although many theories have been proposed. PCI can develop as a primary idiopathic condition, or secondary to different bronchopulmonary and gastrointestinal diseases. Association of PCI with raised intraabdominal pressure has already been reported. PCI is usually benign condition, but can present with serious complications such as obstruction, intussusception and intestinal perforation. Different diagnostic modalities are used in the diagnosis of PCI. Colonoscopy findings of multiple, round submucosal protrusions usually with normal overlying mucosa are not conclusive and include lymphoid hyperplasia, hyperplastic polyposis or colitis cystica profunda in differential diagnosis. Barium enema reveals smooth protrusions but can not exclude multiple polypoid lesions. MDCT evaluation with multiplanar reformations and virtual colonoscopy resolves the diagnostic problem, revealing gas filled cysts in colonic wall. Moreover, MDCT can exclude or detect complications and other pathological conditions such as polyposis, diverticulosis, and tumors. Contributed by