Bilateral Embryonic Vascular Persistence With Focal Aneurysm: Unveiling a Persistent Sciatic Artery Through Imaging: A Case Report.

Persistent sciatic artery is an uncommon embryologic remnant that typically remains clinically silent, yet has the potential to present dramatically when complicated. We report an unusual case of an 80-year-old woman who developed a progressively enlarging gluteal swelling over a year, associated with worsening pain in recent months. Further testing was necessary after ultrasonography revealed internal arterial flow within a cystic mass, despite the initial clinical impression of a soft-tissue neoplasm based on the clinical features. Computed tomography angiography (CTA) confirmed a persistent sciatic artery with a large, thrombosed aneurysm. An unexpected additional finding was the presence of a contralateral persistent sciatic artery, incompletely regressed and asymptomatic. Persistent sciatic artery pathology poses diagnostic difficulties. This case is one of the less common manifestations of this anomaly due to the combination of advanced age, bilateral arterial persistence, and a massive aneurysm. This report, hence, emphasizes the importance of keeping a wide differential diagnosis for gluteal masses and underscores the need for careful imaging evaluation to detect this rare but potentially serious vascular anomaly.