Small cell carcinoma with concomitant adenocarcinoma arising in a Barrett's oesophagus: report of a case with a favourable behaviour.

Most Barrett's oesophagus-associated cancers are adenocarcinomas which occur in a pure form. They are rarely combined with another type of malignancy, such as endocrine tumours. Within the endocrine spectrum, small cell carcinomas (SmCC) usually have a highly aggressive behaviour with a poor prognosis. We report a case of composite SmCC and adenocarcinoma in the setting of a Barrett's oesophagus, in a 54-year-old man. This tumour was identified on a surgical specimen after neoadjuvant treatment with radiotherapy and 5-FU-Cis-platin based chemotherapy. The SmCC component was positive for chromogranin A, synaptophysin, neural cell adhesion molecule and neuron-specific enolase and negative for high molecular weight cytokeratin. The adenocarcinoma component showed a converse phenotype. In our case, the origin of the SmCC component could be explained by the numerous chromogranin A-positive cells observed in the Barrett's oesophagus or by the potential progenitor cells that may be located in the submucosal oesophageal gland ducts and the Barrett's metaplasia. Our report is thus indicative of the high and totipotential risk of Barrett's oesophagus. Moreover, it is particular because of its favourable behaviour, with a 6-year disease-free survival, after neoadjuvant chemoradiation, surgery and postoperative chemotherapy.