[A case of esophageal squamous cell carcinoma with an adenocarcinoma component that dedifferentiated after chemotherapy].

A 69-year-old man was diagnosed with advanced esophageal cancer(well-differentiated squamous cell carcinoma). Neoadjuvant chemotherapy consisting of nedaplatin and 5-fluorouracil(5-FU)was initiated. After two courses of chemotherapy, the patient was judged to have achieved a clinical complete response. The patient then decided against undergoing surgery and opted instead to continue with the chemotherapy, receiving five courses in total. However, the esophageal cancer recurred, and subtotal esophagectomy was performed in January 2011. Squamous cell carcinoma with an adenocarcinoma component, which consisted of poorly differentiated squamous cell carcinoma and tubular adenocarcinoma cells, was observed at the primary site. Metastasis of the cancer to the liver was detected 2 months after surgery. The subsequent administration of four courses of docetaxel to the patient did not result in any beneficial effects, and the patient developed carcinomatous pleurisy and died of this complication in November 2011. The patient survived for a total of 21 months after starting chemotherapy. In this case, the chemotherapy itself may have resulted in the dedifferentiation of a well differentiated squamous cell carcinoma to result in a poorly differentiated squamous cell carcinoma with an adenocarcinoma component.