Combined tubular adenocarcinoma, neuroendocrine carcinoma and adenocarcinoma with enteroblastic differentiation arising in Barrett esophagus

Adenocarcinoma (AC) with neuroendocrine carcinoma (NEC) or enteroblastic (ENT) differentiation rarely develops in Barrett's esophagus (BE). A 76-year-old man was diagnosed with Barrett's AC (cT1bN0M0) and underwent thoracoscopic esophagectomy. A type 0-IIc + 0-Is lesion measuring 26 x 21 mm was macroscopically observed on a background of long segment BE (pT1bN0M0). The tumor comprised three different histological types of carcinoma (NEC, AC with ENT differentiation and moderately differentiated AC). NEC showed positivity for synaptophysin, chromogranin A and insulinoma-associated protein 1 with a Ki-67 index of 60.6%. ENT tumors were immunopositive for AFP and sal-like protein 4, and focally immunopositive for human chorionic gonadotrophin. The amounts of NEC, ENT and AC were 40%, 40% and 20%, respectively. p53 expression was positive throughout the tumor. Rb expression was negative at the NEC, but positive at the ENT and AC. CD4 and CD8 densities were lower in the NEC segment than in the AC and ENT segments, and PD-L1 expression was negative throughout the tumor. Early cancer arising in BE with a combination of tubular AC, ENT tumors and NEC is very rare. Our observations might contribute to understanding the carcinogenetic pathways and tumor microenvironment of NEC and ENT tumors.