A 55-year-old woman, with no medical history, presented with acute right flank pain. She had no history of other urinary complaints. On physical examination, the patient was tachycardic (pulse rate: 100bpm) and tachypneic (respiratory rate: 24 breaths/min), blood pressure was11/6 and temperature was 37.4°.

The abdominal examination showed severe tenderness in the right flank and the right iliac fossa. All blood reports were normal, including C-reactive protein, cell blood count and serum creatinine. Computed Tomography of the abdomen revealed a right hydronephrosis with delayed phase contrast leak and a retroperitoneal mass of 48x36mm of unknown nature, enhanced after contrast injection, which seemed to compress the right ureter causing the forniceal rupture.

A double J ureteral stent was insterted into the right renal cavities with favorable evolution and immediate resolution of pain. Surgical management of the mass was scheduled one month later after the inflammatory phase and resorption of the urinoma. The patient underwent an exploratory laparotomy. Intraoperatively, a tissular retroperitoneal mass of 4 cm was discovered which invadedthe right proximal ureter as well asthe duodenum and the ileocecal pedicle (Figure 1). Resection of the tumor was performed as well as a segmental ureterectomy, right colectomy, and resection of a small portion of the duodenum. Both ureteric and colic anastomosis were then performed along with duodenal suture.

The post operative course was uneventful.