Pneumatosis Intestinalis: Gas-Distended Lymphatic Vessels in Nature
Xianyong Gui, Lihui Qin, Vincent Falck, Yi Zhou, Leslie Eidus, Zu-hua Gao. University of Calgary and Calgary Laboratory Services, Calgary, AB, Canada; Weill Cornell Medical College of Cornell University, New York, NY; University of Illiois at Chicago, Chicago, IL
Background: Pneumatosis intestinalis (PI) is a condition characterized by multiple gas-filled cysts within bowel wall, and it is associated with diverse background diseases. Its etiology is unknown. Several theories postulate that luminal gas dissects bowel wall following mucosal injury, gas-producing bacteria gain access to submucosa through breaches in mucosa, or pulmonary gas tracks via mesentery. In a few studies, a spatial relationship of pneumatosis to lymphoid tissue was noted, and the lymphatic channel was suggested to be the possible gas-transporting pathway. We further investigated this possibility using immunostaining of Podoplanin, a mucoprotein specifically expressed in lymphatic endothelial cells.
Design: 9 cases (M 5, F 4, 32 to 64 y/o) were retrieved from surgical pathology file of Calgary Laboratory Services. 8 cases were diagnosed in resections and 1 in biopsy. Pneumatosis was seen in right colon in 8 cases (including 4 in ascending colon and 1 in cecum) and in small bowel in 1 case. All showed typical pathologic features including polypoid mucosal surface (in 8 cases) and/or multiple cystic spaces within submucosa (+/- mucosa and subserosa) that were mostly covered by multinucleated giant cells (in 8 cases). Immunostainings for Podoplanin (D2-40), Calretinin, WT1, CD31, CD68, and Vimentin were performed on lesional tissue.
Results: A strong immunopositivity of Podoplanin was seen in the lining of cystic spaces in 100% of the case, but not seen in the overlying giant cells. Meanwhile, the lining was negative for Calretinin and WT1, which ruled out the possible mesothelial origin but confirmed the lymphatic endothelial origin. The CD68-positivity of the giant cells proven their reactive histiocytic nature.
Conclusions: Our findings show that PI is resulted from gas-distended lymphatic channels that become the common gas-transporting pipeline in various conditions in which mucosal integrity is impaired. The clinical presentation most likely depends on the entrance of gas penetrating into and the extent and degree of the ballooning of bowel wall lymphatics.
Wednesday, March 21, 2012 9:30 AM
Poster Session V # 276, Wednesday Morning