Myogenic expression in esophageal polypoid tumors.

Four cases of esophageal polypoid tumors composed of squamous cell carcinoma and spindle cell sarcomatous components were investigated. Squamous cell carcinoma was consistently present in the base of the polypoid lesions in all four cases and was also intermingled with spindle-shaped sarcomatous cells in two cases. Metastases in the lymph nodes were observed in two cases: one was squamous cell carcinoma with a sarcomatous component and the other consisted of a pure sarcomatous component. All tumors involved at least the muscularis mucosae. In the sarcomatous region, the tumor was composed of highly anaplastic cells with or without forming interlacing fascicles. Pleomorphism was marked and bizarre giant cell forms were frequent. Mitoses were frequently present. Immunohistochemical study revealed that the anaplastic cells in the sarcomatous component in all cases were immunoreactive to desmin, muscle actin, vimentin, and alpha 1-antichymotrypsin, but were negative for cytokeratin, even in the metastatic tumors of the lymph nodes. The immunohistochemical results favor myogenic differentiation of the anaplastic cells, and these tumors were considered to be true carcinosarcomas composed of squamous cell carcinoma and leiomyosarcoma.