Endocrine cells in renal pelvis and ureter, an immunohistochemical analysis

A systematic detection of endocrine cells in the renal pelvis and ureter was carried out, using Grimelius stain and immunohistochemical techniques. Ninety specimens of pelvic and ureteral mucosae were investigated. Throughout the pelvic urothelium, endocrine cells were very uncommon, patchily distributed, and serotonin-storing. They have been disclosed in only two cases among normal-appearing transitional epithelium. Whether cells so scanty are normal and permanent inhabitants of this territory is debatable. The material examined did not provide opportunity to demonstrate endocrine cells throughout the normal ureter. Surprisingly, one case of supernumerary ureter with an ectopic distal orifice into the urethra harbored abundant serotonin cells. This remarkable endocrine profile, which departed appreciably from that of normal ureter, showed a close similarity with that of the urethra. This raises the question whether such endocrine differentiation might reflect, for this ectopic ureteric bud, urogenital sinus origin rather than wolffian origin.