Lymphoepithelioma-like carcinoma of the esophagus: report of a case with non-progressive behavior.

Lymphoepithelioma-like carcinoma (LELC) of the esophagus is extremely rare and the prognosis has been described to be favorable. Herein, the case is reported of esophageal LELC showing non-progressive course for 1 year. The patient was a 70-year-old Japanese man with a submucosal tumor in the lower esophagus. The tumor was endoscopically regarded as a benign leiomyoma. One year after the first endoscopic examination, the size of the lesion remained unchanged despite no treatment. Histologically, the tumor showed undifferentiated carcinoma associated with dense lymphocytic and plasma cell infiltration. Lymphoid follicles surrounded the tumor cell nests. Immunohistochemically, Ki-67 labeling index of the tumor cells were 76.0%, and there were few single-strand DNA-positive apoptotic cells. In situ hybridization using a digoxigen-labeled Epstein-Barr virus (EBV)-encoded small RNA (EBER)-1 riboprobe failed to detect the presence of EBV infection. Physicians should be aware that esophageal LELC endoscopically mimics benign submucosal tumor. This case may demonstrate that esophageal LELC is a slow-growing tumor and it is related to immune reaction.