Introduction. Urinoma is a rare pathology of childhood, which manifests itself in the accumulation of urine in the perirenal space. In most cases, the cause of urinoma is an obstruction of the urinary system at some level (from the ureteropelvic segment to the urethra). The mechanism of the development of urinoma is damage of the collecting system of the kidney is related to an increase in intrarenal pressure above 35-40 cm of water column, while urine can accumulate both retroperitoneally and intraperitoneally or even in the pleural cavity by extravasation or as a result of damage of the parietal peritoneum. Due to the rare occurrence of this pathology, unified approaches to the treatment of patients with urinoma have not been developed.

Materials and methods. On the basis of St. Petersburg GBUZ DGM KSTSVMT in the period from 2007 to 2020, 7 newborn patients with this diagnosis were treated. Of all the patients, 5 were transferred from the maternity hospital to the neonatal pathology department due to the prenatally diagnosed pathology of the urinary system. However, only one child was suspected of urinoma against the background of hydronephrosis.

Results and discussion. The cause of urinoma in 1 case (14%) was obstructive megaureter, in 3 patients (43%) – hydronephrosis, in 2 (29%) – posterior urethral valve. In 1 patient (14%), the cause of the urinoma was not identified. It should be noted that cystic dysplasia of one or both kidneys was detected in 3 children against the background of the underlying pathology. Clinical manifestations of urinoma ranged from the absence of any symptoms (in 1 case) to the presence of a palpable mass in the abdominal cavity and lumbar region, which caused concern to the child (in 3 patients). CT was performed in 4 patients in order to clarify the nature, location, and possible connection of the cystic formation visualized by ultrasound with the collecting system or the kidney parenchyma. The tactics of treating urinoma were different depending on the specific case. Open intervention was required in 6 children (86%).

Findings. The rarity of such a pathology as urinoma leads to the lack of a single tactic for its diagnosis and treatment. Applied methods of visual determination of perirenal accumulation of urine, such as ultrasound and CT, can not always help to reliably differentiate urinoma from a kidney/abdominal cyst or severe hydronephrosis. In most cases, preference is given to puncture techniques and radical treatment of the underlying uropathy.