Venous cystic adventitial disease presenting as an enlarging groin mass

Venous cystic adventitial disease is an exceedingly rare vascular disorder, with 12 cases reported in the past decade. A 60-year-old woman presented with a painful, palpable groin mass without leg swelling. She was initially thought to have a nonreducible inguinal hernia. A computed tomography scan was obtained that revealed a cystic mass involving the right common femoral vein. Previous imaging revealed that the mass had enlarged over time. In the operating room, the cyst wall was excised without compromising vein integrity. The patient had an uneventful recovery and her pain resolved. We review the presentation, diagnosis, and treatment of this condition. We believe that the rapid evolution of this lesion suggests that an unknown inciting factor triggers its onset and growth.