Ileal conduit stenosis--an enigma.

Ileal conduit stenosis was diagnosed in 12 patients in the period 1981-1994. The time between urinary diversion and this diagnosis was 7-30 (mean 14) years. The clinical picture, i.e. colicky flank pain and/or fever, was produced by upper urinary tract obstruction. Intravenous urography, loopography and looposcopy were used in diagnosis. Treatment consisted of removal of the conduit and replacement by a new ileal loop or a continent reservoir, or partial resection with or without ureteric reimplantation. Light microscopy of the removed conduits showed severe, sometimes transmural inflammation with submucosal fibrosis. Transmission electron microscopy (TEM) demonstrated reduced height of microvilli, presence of glycocalyceal bodies and an increased number of lysosomes. Other subcellular structures were intact. The pathogenesis of the stenosis is obscure. Microvascular insufficiency, infection in conjunction with exposure to urine, reaction to some noxious agent in the urine or immunologic causation have been proposed. This late stenosis seems to arise only when ileum is used as conduit. Its insidious course calls for lifelong observation of the upper urinary tracts in these patients.