Metanephric adenoma with embryonal hyperplasia of Bowman's capsular epithelium: previously unreported association.

We report a case of a 9-year-old boy with focal, segmental glomerulosclerosis who, following peritoneal dialysis, underwent renal transplantation and bilateral nephrectomy. The kidneys showed histological features of embryonal hyperplasia of Bowman's capsular epithelium, an uncommon lesion that is seen most often in patients with chronic renal failure who are being maintained on dialysis. In addition, a 1-cm tumor in the left kidney showed features of metanephric adenoma. Although both lesions are uncommon, they share many similarities on a morphological, immunohistochemical, and ultrastructural basis. This association has not been previously reported and may shed some light on the histogenesis of these recently described lesions.