Esophageal adenocarcinomas usually develop in Barrett's esophagus, typically through the metaplasia–dysplasia–carcinoma sequence, but adenocarcinomas can occur from heterotopic gastric mucosa in cervical esophagus (inlet patch). This report describes the first case of synchronous presentation of adenocarcinoma arising from cervical inlet patch and Barrett's esophagus-related dysplasia in a 76-year-old man. Surveillance CT detected a 3-cm polypoid mass in the cervical esophagus. Endoscopic biopsies confirmed a diagnosis of adenocarcinoma of the cervical esophagus. Barrett's esophagus was present also in the lower esophagus. Histologic examination of the surgically resected specimen revealed the polypoid mass as composed of tubular adenocarcinoma, and was associated with non-neoplastic columnar mucosa representing pre-existing inlet patch. Another isolated cervical inlet patch with intestinal metaplasia was also recognized. In the lower esophagus, high-grade dysplasia was noted within the Barrett's esophagus. Immunohistochemically, the adenocarcinoma associated with inlet patch had intestinal immunophenotype (CDX2-, CD10- and MUC2-positive), whereas the Barrett's esophagus-related high-grade dysplasia showed mixed immunophenotype (MUC5AC- and MUC6-positive, with scattered MUC2-positive goblet cells). Previous studies and our findings suggest that intestinal metaplasia might predispose to the development of adenocarcinoma in the inlet patch. Therefore, endoscopists and pathologists should be aware of rare malignant transformation of inlet patches, especially those with intestinal metaplasia.