Clustering of the upper urothelial tumours in a family.

In a Balkan nephropathy endemic area, 5 siblings developed haematuria over a period of 10 years. 4 of them were operated on and pathohystological examination revealed papillary transitional cell tumours of the renal pelvis and/or ureters. Both these tumours and the Balkan nephropathy affected only 1 generation of the family members. This fact, as well as the other relevant evidence, indicated that environmental factors played an important role in the process of carcinogenesis.