True anterior tibial artery aneurysm in an adolescent with a history of preceding blunt trauma: a case report and literature review

Introduction and importance: True anterior tibial artery (ATA) aneurysms are exceptionally rare vascular lesions, with only a limited number of histopathologically confirmed cases reported in the literature. Their etiology is heterogeneous and includes trauma, degenerative vascular disease, connective-tissue disorders, infection, and idiopathic aneurysmal degeneration. Presentation of case: A 17-year-old female presented with a progressively enlarging, painless, pulsatile mass in the right leg following blunt trauma. Computed tomography angiography (CTA) demonstrated a 2 × 1 cm, contrast-filled saccular lesion arising from the ATA, initially interpreted as a pseudoaneurysm, with a larger surrounding component thought to represent an intramuscular hematoma. The patient underwent aneurysmectomy with tension-free, primary end-to-end arterial reconstruction using continuous 6-0 polypropylene suture. Histopathological examination confirmed a true aneurysm with preservation of all three arterial wall layers. At the 6-month follow-up, the patient remained asymptomatic with palpable distal pulses. At the 1-year follow-up, she remained clinically well, and CTA demonstrated no active contrast extravasation. Clinical discussion: Distinguishing a true ATA aneurysm from a pseudoaneurysm may be challenging, particularly in the setting of preceding trauma, and definitive classification may depend on histopathological examination. Management should be individualized according to the anatomy of the lesion, distal perfusion, and feasibility of arterial reconstruction. Conclusion: A true ATA aneurysm should be considered in the differential diagnosis of a pulsatile leg mass, even after prior trauma. Histopathological examination is important for distinguishing true aneurysms from pseudoaneurysms. Primary end-to-end reconstruction is a feasible, artery-preserving option when tension-free approximation can be achieved.