Pneumatosis cystoides intestinalis in Iran.

Nineteen cases of pneumatosis cystoides intestinalis all affecting adults and all involving the small intestine have been collected in two centres of Iran (Shiraz and Tehran) over a 20 year period, the pathological findings being divided into three groups: pure submucosal, combined submucosal and subserosal, and pure subserosal cysts. Experimental PCI was produced in cadavers using high pressure oxygen insuflation of the lungs, thus lending support to the theory that it has a mechanical origin. Other theories of aetiology include tumour, nutritional deficiencies, gas-forming organisms, alveolar rupture, and acid-base disturbance. In most of the cases presented high intraluminal pressure produced by obstruction appeared to force intraluminal gas through a breach in the mucosa into either the lymphatics or perivascular tissue to produce PCI. It is concluded that the aetiology in the vast majority of adult cases is mechanical in nature and that bacteria seem to play very little part, unlike their role in the PCI of infants.