Primary Basilic Vein Aneurysm: A Case Report and Literature Review.

Basilic vein aneurysms (BVAs) are extremely rare vascular entities, with fewer than 50 cases reported to date. They typically present as soft, compressible, and painless soft-tissue masses. We present a case of a 55-year-old man with a primary symptomatic BVA of the non-dominant forearm, complicated by previous sac thrombosis. Duplex ultrasonography confirmed a fusiform aneurysm measuring 18×15 mm with intraluminal thrombus and partial recanalization. Surgical excision under local anesthesia was performed successfully, without postoperative complications or disruption of the upper-extremity superficial venous outflow. The pathological report confirmed the diagnosis of a true degenerative venous aneurysm. A comprehensive literature review was conducted to summarize current knowledge on the pathogenesis, clinical features, differential diagnosis, imaging modalities, and treatment strategies of BVA.