[Spontaneous urinary extravasation in the retroperitoneum due to ureteral calculi obstruction].

The diagnosis and management of 12 patients with spontaneous urinary extravasation due to ureteral calculous obstruction are described. Contrary to the "frank" rupture most cases can be managed without surgical intervention. The presistence of extravasation must be the reason for tumour exclusion. The renal fibrolipomatosis was seen as the possible late result of the extravasation.