Non papillary insitu carcinoma of urothelium denudes unusually easily. This uncovering produces a character­istic, syndrome of intractable antibio­tic-resistant bacterial cystitis with a granular and velvet appearance on cystoscopy. the exposed stroma histo-logically demonstrate vasodilatation, oedema and leucocytic infiltration re-suiting in clinical symptoms which are the same as those of benign cystitis due to other causes (Riddle et al., 1979; Ooms et al,, 1986 and Boob et al., 1986). The aim of this work is to differen­tiate between denuded areas of car­cinoma insitu and those in benign cys­titis by examination of the superficial stroma. Also to determine if there are significant differences in stromal fea­tures seen in papillary carcinoma and carcinoma insitu, in an attempt to im- prove histological differentiation be­tween folded fragments of bladder mucosa with a lining of carcinoma in­situ and real papillary tumour fragme­nts as it is may be difficult in biopsy material and because of the different therapeutic measure for the two le­sions.