Esophageal Carcinoma with Triplicate Differentiation into Squamous Cell Carcinoma, Small Cell Carcinoma and Adenocarcinoma: a Case Report.

Esophageal carcinoma with multiple differentiation is very rare. The author herein reports a case of esophageal carcinoma with triplicate differentiation (squamous cell carcinoma, small cell carcinoma, and adenocarcinoma). A 78-year-old man was admitted to our hospital because of dysphagia. An endoscopic examination revealed a polypoid tumor (3 x 4 x 3 cm) in the distal esophagus, and biopsy was obtained. The biopsy showed a tumor composed of moderately differentiated squamous cell carcinoma, small cell carcinoma, and adenocarcinoma. The proportions of them were 40% in squamous cell carcinoma component, 50% in small cell carcinoma component, and 10% in adenocarcinoma. There were gradual merges among them. Immunohistochemically, squamous cell carcinoma component was positive for cytokeratins and p53 protein. The Ki-67 labeling was 43%. The small cell carcinoma component was positive for cytokeratin, p53 protein, CD56, and KIT. The Ki-67 labeling was 95%. The adenocarcinoma component was positive for mucins, cytokeratin, p53 protein and CEA. The KI-67 labeling was 52%. The author speculates that this carcinoma arise from totipotent stem cell of the esophagus. The patient was treated by chemoradiation therapy, but died of systemic metastasis 13 months after the initial manifestation.