Thymic carcinomas are rare tumors for which the main treatments have been surgery, radiotherapy, or both. However, the role of chemotherapy is less well-defined. Here, we report a case of advanced thymic anaplastic carcinoma which was suspected to be the primary lesion, yet was successfully controlled despite brain metastases by EACUM combination chemotherapy consisting of cyclophosphamide, adriamycin, cisplatin, 5-FU, and methtrexate. Pathohistological findings on metastatic lesions of the right supracuravicular lymph nodes led to a diagnosis of anaplastic carcinoma. We could not give a diagnosis of thymic carcinoma because the biopsy specimen had not been taken from the thymus. There was no evidence of a primary neoplastic tumor other than thymoma. The patient was still alive 6 years and 9 months after the start of anticancer treatment and was working normally. The findings from this case should be of value to the establishment of effective combination chemotherapy regimens for advanced thymic carcinoma.