Human Epidermal Growth Factor Receptor 2-positive Primary Adenocarcinoma in the Cervical Oesophagus: A Case Report.

Background/aim Cervical oesophageal adenocarcinoma (COA) is extremely rare. We present a case of human epidermal growth factor receptor 2 (HER2)-positive COA that showed repeated recurrences despite multidisciplinary treatments. Case report A 49-year-old male was diagnosed with clinical stage IVA COA that originated from ectopic gastric mucosa. He initially underwent definitive chemoradiotherapy (CRT) (60.0 Gy/30 fractions, 5-fluorouracil, and cisplatin). Two months after CRT, the right supraclavicular lymph node (LN) reenlarged and salvage lymphadenectomy was performed. Immunohistochemical staining revealed a HER2-positive adenocarcinoma. Four months after lymphadenectomy, multiple metastases in the mediastinal LNs and lungs were detected, and S-1, oxaliplatin and trastuzumab were administered. Four months after chemotherapy, the patient presented with new liver metastasis. Further metastasis was prevented by Nivolumab treatment for four months. Conclusion HER2-positive COA may be more aggressive and may require further intensive treatments. This literature review may be helpful in determining treatment strategies for COA.