'Porcelain kidney': case report and review of the literature.

A rare case of pan-subepithelial dystrophic calcium deposition and bone marrow formation in hydronephrosis secondary to obstructive urolithiasis is reported and discussed. An elderly gentleman presented with accelerated hypertension, a nonfunctioning left kidney secondary to obstructive nephrolithiasis with additional pancalyceal calcification. His left retroperitoneoscopic nephrectomy specimen revealed sterile hydronephrosis secondary to an impacted ureteropelvic junction stone and pan-subepithelial fibrocalcific lamellar deposition. Special stains confirmed end-stage renal disease with chronic pyelonephritis with subepithelial dystrophic calcium deposition and evidence of bone marrow formation.