Histological findings after colocystoplasty and gastrocystoplasty

Purpose: We conducted a prospective, long-term assessment of the histological changes that can occur following bladder augmentation with colon or stomach. Materials and Methods: Histological evaluations of biopsies from 44 consecutive patients undergoing augmentation (colocystoplasty in 26, gastrocystoplasty in 18) were performed. Patients underwent endoscopic assessment and tissue sampling at 2 or 4-year intervals following the initial augmentation procedure. Patients with less than 2 years of followup were excluded from the analysis. Specimens were taken from the native bladder, the augment segment (large bowel or stomach) and the anastomotic line. Sections (4 mu.) were examined using standard histological staining methods (hematoxylin and eosin and periodic acid-Schiff) and immunohistochemistry was performed for different markers of neoplasia, cellular proliferation and blood group antigens. Histological findings were correlated with the incidence of stone formation and urinary tract infection. Results: Group 1 consisted of 20 patients undergoing colocystoplasty who met the criteria for study inclusion. Of the patients 10 (50%) had stones, 19 (95%) had a positive urine culture and 6 had no histological changes. While no cases of malignancy were identified, other forms of pathological change were noted in 14 of the 20 patients (70%). Group 2 included 15 patients undergoing gastrocystoplasty who met the criteria for study inclusion. No stones or malignancy were identified in this group. Positive urine cultures were recorded in 2 patients (13%), no histological changes were found in 6 and 9 (60%) had pathological changes. Conclusions: Periodic prospective biopsy evaluation of children who have undergone either colocystoplasty or gastrocystoplasty failed to reveal any histological evidence of malignancy after 10-year followup. However, histological evidence of a premalignant lesion 13 years after followup suggests that screening for premalignant lesions should be initiated no later than 6 to 10 years following enterocystoplasty.