June 09-41-2.indd - Kma.org.kw

144Pneumatosis Intestinalis of Small Bowel in an Adult: A Case ReportJune 2009Fig. 1: Outer surface of small bowel showing multiple air filledcysts (pneumocysts) in grape like mannerFig. 2: Mucosal surface showing “cobblestone” appearanceFig. 3: Pneumocysts in the bowel wallappearance (Fig. 2) with numerous air filled cysts(pneumocysts) in the wall (Fig. 3). The cysts variedin size from 0.2 to 2 cm in diameter. No mass,polyp, diverticula, volvulus, or intussuception wasidentified.Microscopic features: The cysts identifiedgrosslyin small bowel were located in the submucosal(Fig. 4), and subserosal region. They were linedby mostly multinucleated giant cells. No truelining epithelium was seen. There were no featuresof any granulomatous inflammation, necrosis,inflammatory bowel disease, or malignancy.Moderate to severe serositis was observed. Specialstains (Periodic acid-Schiff, Grocott’s methaminesilver, and Gram’s stain) for micro-organisms werenegative.DISCUSSIONPI is rare and preliminary diagnosis depends onclinical and radiological findings. Computerizedtomographic scan is the best imaging modalityFig. 4: Photomicrograph showing submucosal air-filled cysts(H&E, x 40)although plain radiograph also shows characteristicfindings. The pathogenesis has been debated foryears and various explanations have been suggestedby various authors [5,7,9,10] . However the spectrum ofdiseases which underlie the development of thesecysts point toward a multifaceted phenomenon.Two most crucial considerations are: (a) from wherethe gas came, and (b) how it got into the bowel wall.Three possible sources of bowel gas are intraluminalgas, bacterial production of gas, and pulmonary gas.Intraluminal gas can leak to the bowel wall due toincreased intraluminal pressure and mucosal injury,either of them occurring singly [5,6] , or together invarious conditions, e.g., GI obstruction, and ulcerativecolitis [3-5,10] . Bacterial production of gas has beensuggested as an inciting factor for PI and is supportedby the fact that gas disappears after antimicrobialdrug treatment [9] . The original theory of pulmonarygas leaking as a result of alveolar rupture leadingto dissection along vascular planes to mediastinumand then tracing caudally to retroperitoneum