Cystic Adventitial Disease of the Popliteal Vein, a Rare Cause of Lower Limb Deep Vein Thrombosis

INTRODUCTION: Cystic adventitial disease (CAD) is characterised by the accumulation of gelatinous fluid within the adventitial layer of a blood vessel. Over 90% of CAD occurs in the arterial system. Venous CAD most commonly involves the iliofemoral rather than the popliteal segments. REPORT: This is the report of a 49 year old female patient with a previous right leg deep vein thrombosis (DVT). She presented to a vascular outpatient appointment with recurrent right lower extremity swelling. Venous duplex ultrasound showed an ectatic and incompetent right popliteal vein. Computed tomography (CT) venography showed focal ectasia of the right popliteal vein resulting from an eccentric low density cyst with a diameter of 15 mm. Under general anaesthesia, the patient was placed in the prone position. A lazy S incision was performed in the right popliteal fossa. The popliteal vein had an eccentrically thickened lateral bulge. After heparinisation, a longitudinal venotomy, endophlebectomy, and en bloc cyst removal were performed sequentially. Popliteal patch venoplasty was performed subsequently using the ipsilateral small saphenous vein. After six months, the patient remains on rivaroxaban. A follow up venous duplex ultrasound showed vein reflux through a standard calibre popliteal vein without evidence of cyst recurrence. CONCLUSION: Venous CAD is a rare disease and should be considered if previous DVT or symptoms mimicking DVT occur. Cyst resection and reconstruction with vein patch, venous or synthetic graft is the most commonly used strategy and has lower rates of cyst recurrence and need for re-operation.