title: Bilateral anomalous drainage of the posterior divisions of renal veins into the azygos venous system in a 20-year-old woman: a case report.
abstract: 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.
  
  
  METHODS
  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.
authors.affiliation: Department of Adult Cardiovascular Medicine, The Jakaya Kikwete Cardiac Institute, P.O Box 65141, Dar es Salaam, Tanzania. pedro.pallangyo@gmail.com.
authors.forename: Pedro
authors.initials: P
authors.lastname: Pallangyo
authors.affiliation: Department of Radiology, Muhimbili National Hospital, P.O Box 65000, Dar es Salaam, Tanzania.
authors.forename: Frederick
authors.initials: F
authors.lastname: Lyimo
authors.affiliation: Department of Adult Cardiovascular Medicine, The Jakaya Kikwete Cardiac Institute, P.O Box 65141, Dar es Salaam, Tanzania.
authors.forename: Paulina
authors.initials: P
authors.lastname: Nicholaus
authors.affiliation: Department of Adult Cardiovascular Medicine, The Jakaya Kikwete Cardiac Institute, P.O Box 65141, Dar es Salaam, Tanzania.
authors.forename: Stephano
authors.initials: S
authors.lastname: Masatu
authors.affiliation: Department of Adult Cardiovascular Medicine, The Jakaya Kikwete Cardiac Institute, P.O Box 65141, Dar es Salaam, Tanzania.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Janabi
mesh_terms: D000740:Anemia / Q000000981:diagnostic imaging* / Q000209:etiology; D001165:Arteriovenous Malformations / Q000175:diagnosis*; D001401:Azygos Vein / Q000002:abnormalities* / Q000000981:diagnostic imaging; D002637:Chest Pain / Q000000981:diagnostic imaging* / Q000209:etiology; D004322:Drainage / Q000379:methods; D005260:Female; D006801:Humans; D033162:Incidental Findings; D012082:Renal Veins / Q000002:abnormalities* / Q000000981:diagnostic imaging; D012805:Sickle Cell Trait; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Azygos vein; Azygos venous system; Hemiazygos vein; Renal vein anomaly; Renal vein variations; Tanzania