[Four new cases of urothelial inverted papilloma].

Urothelial inverted papilloma account for 2.2% of all urothelial tumours. The preferred location is the bladder; they occur singly and are generally benign, although the majority of authors agrees in treating this entity as a tumour of low aggressiveness. The report contributes four cases of inverted papilloma, three in male patients and the fourth in a female. One was located in the renal pelvis. A revision is made of the etiology, clinical signs and symptoms, diagnosis and treatment, as well as their relationship to surface carcinoma, as it occurs asynchronously in one of the cases described.