A Rare Case of Esophageal Small-Cell Neuroendocrine Carcinoma Presenting With Progressive Dysphagia.

Esophageal neuroendocrine carcinoma (ENEC) is a rare, aggressive cancer that presents with nonspecific symptoms, often mimicking more common esophageal malignancies. We report the case of an 85-year-old man with progressive dysphagia and odynophagia who was found to have a high-grade small-cell neuroendocrine carcinoma (SCNEC) of the mid-esophagus. Diagnosis was confirmed through histopathology and immunohistochemistry (IHC), including synaptophysin, INSM1, and a Ki-67 index near 100%, consistent with a highly proliferative tumor and aggressive biologic behavior. Endoscopic ultrasound (EUS) played a critical role in locoregional staging, demonstrating a T3 lesion without nodal involvement, and providing key information that, together with other clinical factors, informed curative-intent management planning. A multidisciplinary approach enabled timely diagnosis and treatment planning. This case highlights the importance of maintaining a broad differential diagnosis and the value of EUS as an essential tool for accurate staging and management of rare esophageal tumors.