Extrathoracic metastasis of a thymoma is rare ; we report a case of metastasis to the liver of a large solitary thymoma. Biopsy of the mass showed it to be predominantly lymphocytic and histologically the same as a primary thymoma operated on four years previously. On ultrasound and CT scan, the majority of the metastatic tumor was hemorrhagic, necrotic and/or cystic, with a peripheral, irregularly thick solid component and rather thin, smooth encapsulation.