Case Report: A rare case of esophageal adenoid cystic carcinoma treated by endoscopic submucosal excavation combined with radiotherapy.

Adenoid cystic carcinoma (ACC) is a malignant tumor characterized by the biphasic ductal and myoepithelial differentiation, a propensity for perineural invasion and distant metastasis, and relatively slow local progression. ACC primarily arises in the salivary glands, esophageal adenoid cystic carcinoma (EACC)often presents as a submucosal elevation with a smooth surface on endoscopy. This atypical morphological presentation often results in conventional mucosal biopsy sampling of only the normal squamous epithelium, leading to frequent preoperative misdiagnoses of EACC despite endoscopic detection. We report a 70-year-old male with an esophageal submucosal elevation detected via gastroscopy. After endoscopic ultrasound (EUS), the patient underwent endoscopic submucosal excision (ESE). Postoperative histopathology confirmed ACC with positive margins, after which patient received adjuvant radiotherapy and has remained clinically well on follow-up. This study aimed to explore the endoscopic features and diagnostic challenges of EACC and to discuss comprehensive treatment approach integrating endoscopy resection with radiotherapy.