A case of juxtaglomerular cell tumor associated with membranous glomerulonephritis.

The association of membranous glomerulonephritis with benign tumors is rarely described. This report represents, to the best of our knowledge, the first documented account of the simultaneous occurrence of juxtaglomerular cell tumor of the kidney and membranous glomerulonephritis. A young Chinese woman presented with hypertension and proteinuria, whereupon investigations disclosed a renal tumor. She underwent surgical resection, and histologic examination of the tumor revealed CD34-positive uniform polygonal cells with accompanying mast cells, disposed in sheets with focal papillary pattern punctuated by cytokeratin-positive tubular structures. Characteristic rhomboid crystalline granules were identified ultrastructurally. The kidney adjacent to the tumor showed features of membranous glomerulonephritis and hypertensive arteriopathy. Proteinuria improved following tumor resection, but the patient had persistent hypertension attributable to renal hypertensive arteriopathy. This report also highlights the recently described observation of CD34 positivity in juxtaglomerular cell tumors.