High-Flow Congenital Arteriovenous Malformation of the Posterior Chest Wall in a Young Adult: A Case Report on a Rare Anomaly.

Arteriovenous malformations (AVMs) are rare congenital vascular anomalies characterized by direct connections between arteries and veins without intervening capillary beds, resulting in high-flow dynamics. While AVMs commonly affect the craniofacial region and extremities, involvement of the chest wall is exceedingly rare. We describe the case of a 19-year-old male patient who had a painless, progressively enlarging swelling in the right posterior chest wall that had been present since birth. Magnetic resonance imaging revealed a large, high-signal lesion involving subcutaneous and muscular planes of the right posterior chest wall, while computed tomography angiography demonstrated arterial feeders arising from multiple intercostal arteries, confirming the diagnosis of a high-flow AVM. A multidisciplinary approach was employed, beginning with fluoroscopy-guided embolization using polyvinyl alcohol particles and Gelfoam to devascularize the lesion. The patient had a successful en bloc surgical excision performed under general anesthesia one week later. Postoperative recovery was uneventful, and no recurrence was noted at six-month follow-up. This case underscores the importance of a staged, image-guided, and multidisciplinary treatment strategy in managing large, high-flow AVMs in rare anatomical locations such as the chest wall.