Mediastinal malignant epithelioid schwannoma.

A case of mediastinal malignant epithelioid schwannoma (MES) is reported. The tumor probably arose in the vagal nerve, and the trachea was involved. A few months after excision of the primary tumor, multiple metastases appeared in lung, cervical spine, and neck lymph nodes. Microscopically, the tumor showed a highly cellular area resembling melanoma or carcinoma. Immunolabeling was done for S-100 protein, keratin, and melanoma-associated antigen. Examination of the entire lesion and in situ characteristics of the tumor involving the vagal nerve were helpful in making the correct diagnosis. Mediastinal MES, to our knowledge, has not been reported to date in the English-language medical literature.