A rare case report of esophageal neuroendocrine carcinoma mimicking a submucosal tumor: Diagnosis confirmed by endoscopic ultrasound-guided fine-needle aspiration.

Esophageal neuroendocrine carcinoma is an exceedingly rare and aggressive malignancy, accounting for less than 1% of all esophageal cancers. This case report presents a unique instance of esophageal neuroendocrine carcinoma that initially manifests as a submucosal tumor-like lesion, an atypical and under-recognized presentation that can mimic benign conditions such as leiomyomas or gastrointestinal stromal tumors. Conventional endoscopic biopsy, often the first-line diagnostic tool, failed to provide a definitive diagnosis due to the tumor's deep submucosal location and intact overlying mucosa. However, the utilization of endoscopic ultrasound-guided fine-needle aspiration proved instrumental in obtaining sufficient tissue for histopathological and immunohistochemical analyses, confirming the diagnosis of esophageal neuroendocrine carcinoma. This case underscores the critical role of endoscopic ultrasound-guided fine-needle aspiration in diagnosing rare esophageal malignancies that evade standard diagnostic approaches. Furthermore, it emphasizes the importance of considering esophageal neuroendocrine carcinoma in the differential diagnosis of unusual esophageal lesions, particularly when they exhibit unusual features or fail to respond to conventional management. Early and accurate diagnosis is essential for guiding appropriate therapeutic strategies and improving patient outcomes.