Upper gastrointestinal (GI) bleeding is a severe acute disease associated with four main causes, namely, esophageal variceal bleeding, peptic ulcer (PU) bleeding, gastric cancer bleeding and acute erosive hemorrhagic gastritis, and prompt diagnosis and treatment are mandatory [1, 2]. In adults, a fish bone is the most common food-related foreign body [3, 4]. A fish bone can unfortunately pierce the left subclavian artery (LSA) and cause a pseudoaneurysm in rare cases, resulting in an LSA esophageal fistula [3, 5]. Arterioesophageal fistula are rare, but they can cause massive life-threatening bleeding [6, 7]. Here, we report an adult case of a mediastinal abscess corroding the LSA, resulting in delayed but high-risk massive upper GI bleeding.