Introduction and importanceAneurysm of the radial artery is one of the rare cases in the field of vascular surgery, and its diagnosis and management is one of the challenges in this era. Without proper diagnosis and treatment, it may affect the patient's lifestyle and reduce the quality of life because of pain and limitation in activity. Importantly, it may cause limb or life threatening complications including arterial thromboembolism and aneurysm rupture.Case presentationA 50-year-old woman was presented with a true proximal right radial artery aneurysm with the manifestation of an enlarging mass since 2 years ago, which had gradually become painful. The radiologic investigations revealed the presence of an aneurysm in the proximal radial artery. The patient underwent surgery consisting of ligation of the radial artery proximal and distal to the aneurysm and excision of the aneurysm sac. Pathologic examination confirmed the diagnosis.Clinical discussionAny enlarging mass in the pathways of arterial branches can be arterial aneurysm, even if not pulsatile. Prompt physical examination and imaging modalities can help for diagnosis and decision making for either segmental arterial resection or vascular reconstruction.ConclusionRadial artery aneurysm, as a rare but potentially devastating arterial disease should be in differential diagnosis of any forearm mass and managed promptly.