The first reported case of left renal vein fenestration.

PURPOSE: Vascular fenestrations are mostly seen in the arterial system and cerebral vessels, but they can be seen rarely in the venous system. In this article, we aimed to present the first case of left renal vein fenestration, which has not been previously reported in the English literature to the best our knowledge.

METHODS: Computed tomography angiography (CTA) examination was performed on a 40-year-old male patient who presented with rectal bleeding, and iron deficiency anemia, detected hemorrhoids in colonoscopy, and was planned for superior rectal artery embolization.

RESULTS: In CTA examination, a fenestration in the middle part of the left renal vein was detected. The fenestrated segment length was measured approximately 3 cm. The diameter of anterior and posterior channels were 7.66 and 6.01 mm, respectively. The 2.85 mm diameter inferior segmental artery of the left renal artery was passing between the anterior and posterior channels of the fenestrated segment, and there was a slight indentation of this artery to the posterior canal.

CONCLUSION: Although venous fenestrations are rare, they can also be seen in the renal venous system, and can be detected with CTA. It is important for radiologists to be aware of this situation, to increase its detectability and to prevent iatrogenic injury in possible surgical procedures. And also as in our case, left renal vein fenestration may be one of the causes of microscopic hematuria.