The mucosal changes and pathogenesis of pneumatosis cystoides intestinalis.

The clinical and pathologic findings in 11 patients with pneumatosis cystoides intestinalis (PCI) are described. Symptoms were variable but localized to the gastrointestinal tract. Only one patient had obstructive airway disease. Although gas cysts of varying sizes were present in the colonic wall in all cases, distinctive changes were also observed in the mucosa. Architectural disturbances were seen in 11 of 13 specimens, and changes mimicking those of inflammatory bowel disease, including cryptitis, crypt abscesses, chronic inflammation, and granulomas, were present. In addition, crypt dilation and partial crypt rupture, with formation of intramucosal cysts, were seen in association with clusters of small gas cysts in the lamina propria. The transgression of gas cysts through the muscularis mucosae and the presence of larger giant cell-lined cysts in the submucosa suggested entry of gas generated in the colonic lumen or within inflamed crypts from the mucosal aspect. Other postulated pathogeneses of PCI are discussed.