The colovesical fistula in congenital pouch colon: a histologic study

Purpose

The aim of this study was to perform a detailed histopathologic examination of the terminal colonic pouch and the colovesical fistula (CVF) excised during surgical management of male patients with the more severe forms (types I/II) of congenital pouch colon (CPC) associated with anorectal agenesis.

Methods

From January 2005 to December 2006, 25 male patients with types I/II CPC underwent abdominal exploration with dissection of the terminal portion of the colonic pouch and associated CVF till the bladder, division-ligation of the fistula, and excision of the colonic pouch. In 6 of the 25 patients, a complete dissection of the fistula to the bladder was possible, and in them, the terminal portion of the colonic pouch and the CVF were subjected to detailed histopathologic examination. The 6 patients included 3 newborns in whom this surgery was performed as a primary procedure, and 3 patients aged 3 months, 15 months, and 2 years, respectively, in whom a window colostomy of the pouch had earlier been performed. After due processing, multiple sections from the specimens were stained using the routine H&E method and examined under the microscope under different magnifications.

Results

In 4 specimens, the epithelial lining of the CVF consisted of transitional stratified epithelium with underlying anal/urethral glands. In 2 specimens, obtained from patients 15 months and 2 years old, respectively, the lining was of nonkeratinizing, stratified squamous epithelium. Other findings included aganglionosis in the muscle layers (n = 2), submucosal and subserosal fibrosis (n = 1), and thickening of muscle layers in the fistulous portion, suggestive of the presence of an internal sphincter (n = 2).

Conclusions

The CVF in patients with types I/II CPC shows histologic features of the normal anorectal canal.