Venous Adventitial Cystic Disease of the Lower Extremities Mimicking Deep Vein Thrombosis: A Five-Case Series

Venous adventitial cystic disease (VACD) is a rare vascular disorder characterized by mucin-filled cysts in the venous adventitia. We encountered five patients who presented to our vascular clinic with an initial diagnosis of deep vein thrombosis (DVT) but were later diagnosed with VACD on imaging. The patients were aged 64-81 years; lesion locations included the common femoral vein (n=3), external iliac vein (n=1), and popliteal vein (n=1). Four patients underwent surgical intervention, and one patient received conservative management with medical therapy. All surgically treated patients demonstrated improvement in leg swelling after complete cyst excision. One of the two patients with concomitant thrombus developed a massive pulmonary embolism with hemodynamic instability following catheter-directed mechanical thrombectomy. VACD can mimic DVT; however, computed tomography together with duplex ultrasonography is usually sufficient for differentiation. Thrombosis may occur secondary to outflow obstruction, and complete cyst excision remains the treatment of choice.