Transitional cell carcinoma of the renal collecting tubules ("renal urothelioma").

Abstract

Carcinoma of the renal collecting tubules is presented, for the first time in the literature, by a systematic description of 18 renal specimens from cases with or without pelvis carcinoma. The study revealed a surprisingly high incidence of carcinoma in the collecting tubules in association with carcinoma of the pelvis (20%), but as a primary tumour, independent of the pelvic growth. In cases of invasive extension, it is also possible to distinguish between the two localizations of carcinoma by histological criteria. The finding of papillary structure, umbrella cells with keratohyaline or parakeratosis demonstrates that we are dealing with a carcinoma originating in the urothelium of the collecting tubules ("renal urothelioma") corresponding entirely to carcinomas of the urinary tract. In a modification of the WHO histological grading of urinary tract tumours, the frequency of grades, I, II, and III is stated for urothelioma and pelvis carcinoma. Perusal of the 18 case records, on the other hand, did not divulge conclusive data as to whether smoking or the use/abuse of analgesics had been operative as carcinogenic factors.