Bilateral anomalous drainage of the posterior divisions of renal veins into the azygos venous system in a 20-year-old woman: a case report

BACKGROUND Renal vein anomalies are relatively infrequent and generally asymptomatic. Preoperative knowledge of such variants is, however, of paramount importance in several angiographic and surgical procedures including renal venography, renal vein sampling, spermatic embolization, and renal transplantation. Inadequate knowledge and failure to recognize such anatomic variations may lead to several operative hazards including hemorrhage, nephrectomy, and even death. CASE PRESENTATION We report a case of bilateral anomalous drainage of the posterior divisions of renal veins into the azygos venous system in a 20-year-old woman of African descent from Tanzania who presented to us with a 12-year history of recurrent anemia. She had anemia, a positive sickling test, and hemoglobin electrophoresis revealed a sickle cell trait (AS). She underwent computed tomography angiography of her chest and abdomen to rule out the presence of arteriovenous malformations. Aortography findings were normal but venography results revealed features of tortuously dilated azygos and hemiazygos veins each receiving blood from its respective posterior division of renal vein. CONCLUSIONS Although venous anomalies are relatively infrequent and generally lack a clinical significance, a thorough understanding of embryologic development and its associated errors is of immense importance in equipping angiographers and surgeons to select appropriate interventional/operative techniques, anticipate risks, and prevent intervention-related complications.