Histological adaptation of orthotopic ileal neobladder mucosa: 4-year follow-up of 30 patients.

Abstract

For 4 years we have monitored the histological evolution of ileal neobladders in a single cohort of 30 patients in order to systematically describe the histological changes occurring after surgery. The aim of the study was to evaluate the long-term evolution of many histological parameters with functional relevance as to the metabolic outcome of the reservoirs. Ileal samples were collected during surgery and by random biopsies during cystoscopy 6, 12, 18, 24, 36 and 48 months later. At each step qualitative and quantitative assessment of the histological and cytological conditions of the samples was carried out. Morphological changes develop relatively early but the situation tends to level out in about 1 year. The morphological changes are topographically uneven and, although mucosal flattening becomes progressively prevalent, areas with shortened villi persist indefinitely. Goblet cells prevail over enterocytes and the secretive pattern shifts towards sialomucins. The overall replication rate decreases initially but tends to restore in 1 year. Dysplasia or atrophy were never recorded. The 4-year systematic follow-up revealed a typical histological adaptation pattern in the ileal neobladder without signs of dysplasia. The changes seem to be induced by the aggressive environment and develop in the time lag required for functional adaptation of the epithelium.