# Recurrent Deep Vein Thrombosis in a Middle-Aged Woman Due to Congenital Absence of the Inferior Vena Cava: A Case Report

## TL;DR

A middle-aged woman experienced recurring blood clots in her leg due to a rare birth defect involving the absence of a major vein.

## Contribution

This case report highlights a rare anatomical cause of recurrent deep vein thrombosis linked to congenital absence of the inferior vena cava.

## Key findings

- The patient had a congenital absence of the inferior vena cava, leading to anomalous venous drainage.
- Recurrent deep vein thrombosis was attributed to stagnant and turbulent blood flow from the anatomical defect.
- Surgical thrombectomy was required to treat the occlusive thrombosis in the left lower extremity.

## Abstract

Deep venous thrombosis (DVT), either as an initial or recurrent event, is a common problem hematologists encounter while caring for hospital inpatients. It is caused by a variety of factors, sometimes anatomic in nature, and is managed with medical anticoagulation and, in some cases, procedural interventions such as mechanical thrombectomy. A 53-year-old woman, with a history of DVT of the lower extremity four years prior, presented to the emergency department with rapid development of swelling and pain in the left lower extremity after missing two doses of her anticoagulant. She was found to have an occlusive DVT in the left lower extremity requiring surgical thrombectomy. A computed tomography scan of the abdomen and pelvis showed the absence of the inferior vena cava with collaterals draining into the azygos vein. She had negative thrombophilia testing. The initial and recurrent thrombotic events were attributed to stagnant and turbulent blood flow due to anomalous venous drainage from the lower extremities.