Neuroendocrine carcinoma of esophageal and gastric cardia: clinicopathologic and immunohistochemistry study of 80 cases

Neuroendocrine carcinoma (NEC) of the esophagus and gastric cardia is a rare tumor, and the Chaoshan region has one of the highest incidences of esophageal and gastric cardia cancer (GCC) worldwide. The aim of this study was to characterize the clinicopathologic features of esophageal NEC (n = 67) and gastric cardia NEC (n = 13) cases identified over a 9-year period in the Chaoshan region. Esophageal NECs were either purely NEC (n = 47) or mixed with squamous cell carcinoma or adenocarcinoma (n = 20). For GCC; pure NEC was found in 5 cases, whereas 8 cases were mixed with adenocarcinomas. The majority of esophageal and gastric cardia NECs was of the small cell type, and 24/67 esophageal and 5/13 gastric cardia patients were found with lymph node metastasis. Immunohistochemistry was performed in all cases, and positive staining for synaptophysin (Syn) was found for all cases, with half the esophageal NEC cases being also chromogranin A (CgA)-positive. In the multivariate Cox regression model, lymph node and further metastasis were independent prognostic factors for esophageal NEC. Our study revealed the clinicopathological features of esophageal and gastric cardia NECs in the Chaoshan region and found mixed NECs patients may have a better prognosis than pure NECs patients, which may provide therapeutic clue for treating this rare tumor.