Classification of congenital pouch colon based on anatomic morphology

Congenital pouch colon (CPC) is an extremely rare variant of anorectal malformation (ARM), in which varying lengths of the colon is replaced by a dilated pouch accompanied by a fistula communicating with the genitourinary tract. The aim of this study was to determine the incidence and prevalence of various forms of CPC and to classify it according to anatomic localization of malformation.

During a period of 10 years, from 1996 to 2006, 390 patients with ARM were presented and managed at the Rabindra Nath Tagore Medical College, Udaipur, Rajasthan. CPC patients were identified at the time of presentation after abdominal films, and the anomaly was classified according to the form of pouch presentation only during surgical exploration.

Of the total number of ARM cases, the incidence of CPC was 17.2% (67 cases); however, it constituted 55.8% cases of high ARM. Among the CPC patients, type 1 was documented in 19 (28.4%), type 2 in 17 (25.4%), type 3 in two (3%), type 4 in 25 (37.3%), and type 5 in one (1.5%). Multiple large colon segmental dilatations were documented in one patient (1.5%); and in two patients (2.9%), the type of CPC was not known.

Classification based on the anatomic morphology has the advantage of identifying the pouch based on the segment of the colon involved, rather than the previous classification based on the length of the colon.