December 29, 2017
Embryonal Hyperplasia of Bowman’s Capsule Epithelium
H&E and PAS-stained sections from the kidney of an 8-year-old male with advanced nephrosclerosis of unknown etiology. An exuberant proliferation of epithelial cells with an embryonal or immature appearance, arranged in a tubular and nodular pattern, is seen surrounding globally sclerotic glomeruli. This unusual finding termed “embryonal hyperplasia/metaplasia of Bowman’s capsule epithelium” has been described in patients with end-stage renal disease on long-term dialysis. More recently, this finding has also been associated with WT1 mutations in patients with Denys-Drash syndrome and isolated diffuse mesangial sclerosis. The clinical significance of this finding is yet to be determined.
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2. Fukuzawa R, Eccles MR, Ikeda M, et al. Embryonal hyperplasia of Bowman’s capsular epithelium in patients with WT1 Pediatr nephrol. 2003; 18: 9-13