Primary amyloidosis of renal pelvis with duplicate collecting system

A case of primary amyloidosis localized to the inferior renal pelvis of a kidney with a duplex collecting system is described. The onset of gross hematuria and mild flank pain necessitated investigations which yielded a clinical impression of tumor within the lower pelvis of a duplex collecting system. At laparotomy a grossly hemorrhagic-appearing mass in the lower pelvis was noted and a left ureteronephrectomy was undertaken. Histologic examination of the surgical specimen revealed amyloid deposition within the inferior pelvis, the corresponding distal portions of the papillae, and the most proximal ureter. Amyloid was not present elsewhere within either the renal parenchyma or the superior collecting system.