[Nephrogenic metaplasia of the bladder in renal transplant patients]

Nephrogenic metaplasia of the bladder is rare; less than one hundred cases have been reported. Four personal cases and 16 cases reported in the literature concerning renal transplant patients demonstrate that the frequency of this disease is much higher in this group than in the general population. The symptoms and signs, age of onset, macroscopic and microscopic appearance of the lesions correspond to the description in non-transplant patients, apart from the preferential site adjacent to the reimplanted ureter and the presence, in two cases, of cells with virus-like inclusions, one of which corresponded to CMV infection. The traumatic factor in these patients is not sufficient on its own to explain the relative frequency of this lesion in renal transplant patients. The role of immunosuppression, resulting in a reduction of "immunological surveillance", is possible; this metaplasia usually has a benign course, but this high risk population must be carefully monitored for the development of this lesion.