THE VESICOURETERAL JUNCTION IN 3 CASES OF PRIMARY OBSTRUCTIVE MEGAURETER ASSOCIATED WITH ECTOPIC URETERAL INSERTION

Objective To examine the histological structure and autonomic innervat ion of the vesico-ureteric junction (VUJ) in three cases of primary ob structive megaureter occurring in association with ectopic ureteric in sertion. Patients and methods Specimens of VUJ were obtained from one male and two females with primary obstructive megaureter and ectopic u reteric insertions. Serial frozen sections were cut and stained with e ither Masson's trichrome or immunostained for protein gene product (PG P 9.5: a general nerve marker) or dopamine beta-hydroxylase (DPH), a m arker for noradrenergic nerves, Results In each case examined the term inal ureter was encircled by a thick collar of smooth muscle on the in side of which lay normal narrow-diameter longitudinally orientated ure teric muscle bundles. Loose connective tissue separated the surroundin g detrusor muscle from this abnormal muscle collar, which was formed o f distinctive smooth muscle cells arranged in a meshwork, The autonomi c innervation of the ureteric and detrusor muscle bundles was similar to that previously reported for the normal VUJ while the thick muscle collar was richly innervated by D beta H-immunoreactive noradrenergic nerves, Conclusion The presence of an additional smooth muscle collar surrounding the terminal ureter may impede the normal flow of urine fr om ureter to bladder and be the cause of megaureter in these patients, We propose that the presence of this muscular collar arises from the developmental anomaly and suggest that these cases represent a subgrou p that requires early surgical treatment.