[Spontaneous pneumopyelography: ureterocolic fistula caused by rectosigmoid carcinoma].

We present a case of ureterocolic fistula, secondary to a rectosigmoid carcinoma. The infrequency of these ureterocolic fistulae, contrasts with the more usual vesicointestinal ones. In our case, the diagnosis of pathological communication arose from the presence of gas in the excretory tract, after ruling out all those processes which could have led to a similar situation. In agreement with the world literature consulted, we confirm the great difficulty in tracing the course of the fistula by the usual means of diagnosis, in view of the minimal size of the pathological communication and the frequent obstructive behaviour of the fistula itself.