Non-traumatic true superficial temporal artery aneurysm. A rare condition with precise pathological features.

Introduction and importance: Non-Traumatic True superficial temporal artery (STA) aneurysm is a very rare condition. Only around 63 cases have been reported in the literature up to date [1]. Unfortunately, most of published cases lack proper pathological description. Moreover, researchers found that 12.5 % of true STA aneurysms were associated with risk of co-existing other sites' vascular lesions [2,3]. In this paper, we are going to describe case of Non-traumatic true STA aneurysm and illustrate detailed pathological description.

Case scenario: A 31-year-old man presented with a painless lump over the left temporal region of one year's duration. The lump was 2 × 2 cm expansile and pulsated. Doppler ultrasound confirmed the diagnosis of STA aneurysm and 3D CT angiography used to rule out other vascular lesions. Aneurysmectomy was performed. Histologic examination revealed three layer of the arterial wall.

Clinical discussion: Pulsatile swelling over the temporal region is the common presentation of Non-Traumatic True STA. Further evaluation by 3D CT angiography is crucial to rule out other sites' aneurysms. In untreated NT STA there will be 1.6 % risk of hemorrhagic rupture [1].

Conclusion: To the best of our knowledge, this is one of few case reports with detailed histologically finding verified true (spontaneous) STA aneurysm. This case report sought to raise the awareness for proper evaluation of head swelling along with management interventions and follow up.