Primary adenosquamous and squamous cell carcinoma of the upper urinary tract. Report on three cases

Three cases of adenosquamous cell carcinoma and squamous cell carcinoma of the upper urinary tract are presented. The fact that the urothelium normally has no glandular or squamous structures renders the pathogenesis of these tumours interesting. The process is assumed to begin with an urothelial metaplasia resulting from a reaction to chronic irritation, leading to dedifferentiation, dysplasias and, in the end, to a squamous cell carcinoma or adenocarcinoma. The relevant medical histories include chronic episodes of pyelonephritis or nephrolithiasis. Diagnosis, therapeutic approaches and prognosis of these rare tumours are discussed.