A 51-year-old woman with no significant history of disease had been suffering from constipation for the past year, and had abdominal strain and rectal tenesmus during the past three days. During the examination, the only significant symptom was pain in the epigastrium and in the left iliac fossa with no reaction or peritonism. A complete blood test was performed, which showed normal results, including thyroid hormones. Gastroscopy revealed the presence of a small hiatal hernia without complications, and a Helicobacter pylori-associated erosive duodenitis, which was treated with the standard eradicating treatment. An ileum-deep colonoscopy showed 2 polyps in the ascending colon and 4 in the sigma, all of them small in size that were subsequently treated with argon. In the descending colon several elevated areas of different sizes were identified, covered by normal mucosa that collapsed after puncturing with a sclerosis and aspiration needle, which suggested pneumatosis of the colon (Figs. 1 and 2). Pneumatosis cystoides intestinalis (PCI) is defined as the presence of gas-containing cysts in the submucosal and serosal layers of the small and large bowel. The first description was given by Du Vernoin as a post-mortem observation (1). It is a rare disease of uncertain etiology. In 1974 Shallal et al. collected 410 cases from the literature (2). For unknown reasons it is more frequent in men aged between 30 and 50, and gas may remain in the cysts for long periods. Three theories exist (3) to explain the pathogenesis of PCI: the mechanical theory, which states that the gas, coming both from the intestinal lumen and the serosal layer, dissects the intestinal mucosa; the bacterial theory, according to which the gas formed by bacteria accesses the submucosa through small erosions; and finally, the biochemical theory, which suggests that bacteria in the intestinal lumen produce high quantities of hydrogen gas from carbohydrate fermentation. In many cases, PCI is a casual finding. When symptoms exist, the most frequent are: diarrhea, mucous secretion, rectal bleeding, constipation, pain, and abdominal strain. PCI in the small bowel may cause complications in the ileum, invagination, volvulus, and partial or total obstruction (1). The diagnosis can be made with plain abdominal X-rays, opaque enema, CAT, ultrasonography, MRI, and colonoscopy, although abdominal X-rays is the most reliable examination (4). Asymptomatic patients do not need any specific treatment. Symptomatic patients may be treated with high oxygen flow
