Rare Adventitial Venous Cyst Mimicking Deep Vein Thrombosis: A Diagnostic Pitfall-A Systematic Review of Diagnostic Challenges, Imaging Features, and Optimal Treatment Strategies.

Adventitial cystic disease (ACD) is a rare vascular condition, representing approximately 0.1% of all vascular diseases, with about 325 cases reported in the literature since its first description in 1947, including 72 venous cases. This study aims to highlight the diagnostic and therapeutic challenges of venous ACD, which is frequently misdiagnosed as deep vein thrombosis (DVT), femoral varices, aneurysms, venous tumors, or lymphadenopathy due to its rarity. Clinical, imaging, and treatment data from reported cases of venous adventitial cystic disease (VACD) were reviewed. The disease most commonly involved the common femoral vein (56%) and external iliac vein (24%), with less frequent involvement of the saphenous and popliteal veins (7%). Symptoms commonly mimic deep vein thrombosis (DVT), with unilateral swelling resulting from progressive cyst enlargement and subsequent venous luminal stenosis. Doppler ultrasound typically shows a hypoechoic lesion in the venous wall with preserved flow and normal D-dimer levels, while CT angiography and MRI confirm an adventitial cyst occupying ≥ 90% of the lumen without thrombus. Surgical intervention, particularly transadventitial cyst evacuation with excision, is the preferred method of treatment due to lower recurrence rates (7-20%) as compared to cyst aspiration and drainage with higher recurrence (83.3%). These findings highlight the need for heightened clinical suspicion and advanced imaging to optimize the diagnosis and management of venous ACD and reduce misdiagnosis and recurrence. Further studies are needed to optimize diagnostic protocols and treatment strategies, but the limited number of cases hampers meaningful scientific research.