A case of esophageal sarcomatoid carcinoma with molecular evidence of a monoclonal origin.

A case of polypoid tumor of the esophagus consisting of a sarcomatous tumor partly covered with superficial squamous cell carcinoma is described. The sarcomatous component consisted of anaplastic spindle and pleomorphic tumor cells that mimicked malignant fibrous histiocytoma (MFH). Both the sarcomatous and carcinomatous components were positive for p53 immunohistochemically. Further molecular analysis revealed that the two components had the same somatic mutation in the p53 gene. These results suggest a monoclonal origin of this biphasic tumor.