A Case of Aortoesophageal Fistula Mimicking a Subepithelial Tumor

An aortoesophageal fistula (AEF) is a rare but often fatal cause of upper gastrointestinal bleeding. Early diagnosis is challenging because clinical presentations are frequently atypical, which often leads to diagnostic delays. Here, we report the case of an 83-year-old man with an AEF in the mid-esophagus that appeared as a subepithelial tumor (SET)-like lesion. Endoscopic ultrasonography (EUS) revealed a heterogeneously hypoechoic lesion with multiple anechoic areas involving the submucosal and muscularis propria layers, raising concern for a possible malignant tumor. EUS-guided fine-needle biopsy resulted in blood spurting from the lesion, which was successfully controlled with endoscopic clipping. Subsequent contrast-enhanced chest CT confirmed a descending thoracic aortic aneurysm associated with an AEF, and emergency thoracic endovascular aortic repair was performed to prevent catastrophic hemorrhage. Therefore, when a SET-like lesion is detected in the mid-esophagus, careful assessment of pulsation through endoscopy and evaluation of aortic continuity and vascular flow using Doppler or contrast-enhanced EUS are essential for the early diagnosis of AEF.