The extent of carcinoma in situ in urinary bladders with primary carcinomas

The occurrence of carcinoma in situ was examined in a consequtive series of cystectomy specimens from 43 patients. All patients were suffering from or had been suffering from primary bladder cancer. Carcinoma in situ was defined as a definitive polymorphia of enlarged nuclei with abnormal chromatin structure in non-tumour bearing areas. It was found in 26 bladders. By means of a systematic technique of cutting the specimens, the extent of the alterations was quantitied, relating the number of blocks containing the alteration to the total number of blocks in which the changes possibly might be present. The extent of carcinoma in situ ranged from 2 to 81% with an average of 20%. The distribution of the alterations was unpredictable, often strongly focal, most often in continuation of the tumour. In one specimen, the margins of resection were involved. The extent was largest in bladders with poorly differentiated tumours. A temporal relationship between in situ carcinoma and invasive carcinoma could not be shown, as regards tumour size and duration of clinical symptoms. The morphology of the changes is discussed seen in the light of variations in the normal epithelium lining the lower urinary tract. Minor degrees of atypia of the epithelium showed rather bad reproduction. The dominating occurrence of carcinoma in situ in bladders with poorly differentiated tumours may either be a manifestation of a biological difference between tumours of different grades of differentiation or that the morphological criteria used correspond to the in situ type of poorly differentiated tumours.