A 55-year-old Caucasian man presented with a three-day fever, chills and abdominal pain. His medical history indicated that he had hypertriglyceridemia and hypertension. His physical examination was positive for fever (38.3°C), tachycardia (110 beats/minute) and tenderness upon palpation of his left flank. His initial laboratory evaluation showed leukocytosis (18,600), acute renal failure (creatinine 3.8 mg/dL; baseline creatinine 1.2 mg/dL) and numerous white blood cells (WBCs) in his urine. A computed tomography (CT) scan of his abdomen and pelvis showed the presence of left hydronephrosis and an obstructing ureteral stone with a diameter of 1.5 cm. Our patient was diagnosed with left pyelonephritis. He was immediately commenced on broad-spectrum antibiotics. A left percutaneous nephrostomy was also immediately performed on our patient. His sepsis and acute renal failure subsequently improved. After a ureteral stent placement, our patient underwent an internalization of the nephrostomy. During an injection of contrast agent in his left caliceal system, we were able to visualize his left renal vein. At this point, however, our patient was clinically stable, had no hematuria, and maintained a stable hemoglobin level. Finding no convenient explanation for this interesting radiological finding, we initially suspected an iatrogenic renal veno-caliceal fistula.