RESUMO
INTRODUCTION: Duplicated renal collecting system is one of the most common congenital upper urinary tract abnormalities. Duplex system with ectopic obstructive megaureter in the prostatic urethra is rare and exceptionally revealed in adulthood. PRESENTATION OF CASE: We present a rare case of a 72-year-old man without any previous history of urinary symptoms, admitted through the emergency department for altered general condition associated with fever for several days. Investigations have identified left complete duplex system and intraprostatic obstructive megaureter manifesting as acute pyelonephritis. The evolution of acute pyelonephritis was favorable under urine drainage by percutaneous nephrostomy tube and antibiotherapy. Given the multiple comorbidities of the patient, radical surgical treatment by left upper pole nephrectomy was ruled out and we opted for an iterative change of percutaneous nephrostomy tube. DISCUSSION: We briefly review the pathophysiology, diagnosis and therapeutic aspects. CONCLUSION: Early diagnosis and treatment of complicated duplex system is important. Urologists should keep this anomaly in mind.