Extrathoracic metastases of thymomas are extremely rare, occurring in less than 2% of cases. We present a case of metastatic thymoma in the liver diagnosed by aspiration biopsy. A fine-needle aspirate from a hepatic mass of a 65-year old man who had a history of malignant thymoma locally invading pericardium was examined. Nests of epithelial cells with few scattered lymphocytes were present. The nuclei of the epithelial cells were round to oval and appeared relatively uniform and regular, with fine chromatin pattern. They had one or two, small but lather conspicuous nucleoli. Unlike previous reports on the findings of the aspiration cytology of thymomas, the characteristic biphasic pattern was not present in this case.