NEPHROGENIC ADENOMA IN RENAL-TRANSPLANT RECIPIENTS - A TRULY BENIGN LESION

Objectives, Nephrogenic adenoma is a benign metaplastic lesion of the urinary bladder, reported to occur as a response to inflammation, trau ma, intravesical therapies, and after renal transplantation. The aim o f this study was to evaluate on the basis of chromosomal analysis whet her nephrogenic adenoma really is benign. Methods. Twelve renal transp lant recipients with histologically verified nephrogenic adenoma were analyzed for numerical aberrations of chromosomes 7, 9, and 17. Result s were related to total DNA content, p53 and Ki-67 positivity, and cli nical outcome. Ten patients with superficial bladder cancer and 10 hea lthy renal transplant: recipients formed the control groups. Results. AII 12 patients with nephrogenic adenoma had monosomy 9 in a mean of 2 4.3% (range 20% to 50%) of the evaluated cells; 3 patients had an addi tional trisomy 7 in a mean of 8% (range 6% to 10%) of the counted cell s. Chromosome 17 was disomic in all patients. DNA histograms were dipl oid in 11 of the 12 patients and aneuploid in 1 patient. No p53 and Ki -67 positivity was present in this group. All patients with superficia l bladder cancer had monosomy 9 in a mean of 79.8% (range 75% to 85%) of the counted cells. Two patients were found to have an additional tr isomy 7 in 50% and 65% of the cells, respectively. The latter had an a neuploid histogram; the others had haploid/diploid histograms. p53 was negative in all specimens. Ki-67 positivity was present in 70% of the se patients. All healthy transplant recipients had disomic chromosomal patterns according to diploid DNA histograms and negative immunocytoc hemical results. Conclusions. Even if in a lower percentage of cells, aberrations of chromosome 7 and 9 were detected in nephrogenic adenoma . It therefore cannot be excluded that nephrogenic adenomas in immunos uppressed renal transplant recipients may develop into malignant lesio ns. (C) 1998, Elsevier Science Inc. Ail rights reserved.