Urinoma: A Rare but Potential Differential of Acute Abdomen

Urinoma is an encapsulated collection of extravasated urine in the retroperitoneal space. This rare and potentially dangerous event can occur spontaneously or iatrogenically varying from asymptomatic cases to acute abdomen. The initial diagnostic modality is ultrasound. Suspicious ultrasound findings are confirmed by CT or MRI. Treatment depends on the inciting factor and varies from conservative management to interventional drainage procedures. We report the case of a male patient with known urothelial carcinoma of the urinary bladder who presented acutely with a complaint of progressive painful swelling in the right lumbar region. Imaging revealed a breach in the right ureter leading to urinary extravasation and the formation of progressively enlarging urinoma extending to the contralateral lumbar region. Based on radiological diagnosis, the patient was urgently referred to a urologist. Spontaneous renal rupture should be one of the differentials of a patient presenting with acute abdomen as it can lead to a rare and potentially threatening condition of urinoma.