Synovial Cyst of the Antecubital Fossa Mimicking a Brachial Artery Pseudoaneurysm: Report of a Case

Pseudoaneurysms of the brachial artery are common following a percutaneous cardiac catheterization. Synovial cysts are a commonly identified entity in patients with rheumatic diseases as well. We present a rare case of a synovial cyst in the elbow masquerading as an iatrogenic pseudoaneurysm of the brachial artery. A 51-year-old female patient presented with a pulsatile and painful mass in the right antecubital fossa. The medical history revealed a recent diagnostic cardiac catheterization at the same site and rheumatoid arthritis under oral treatment. Imaging investigations were not fully diagnostic. Because of the clinical suspicion of a thrombosed pseudoaneurysm, exploratory surgery was indicated. The pathologic examination of the specimen confirmed the diagnosis of a synovial cyst. Ultrasonography and computed tomography imaging are valuable in the everyday clinical practice but they do not always exclude an iatrogenic pseudoaneurysm, especially when the medical history is suspicious. Surgical removal is the proper treatment and pathologic examination sets the final diagnosis in such cases of diagnostic difficulty.