Hepatic lesion of invasive thymoma: possibility of direct invasion.

Thymomas grow slowly but tend to invade the surrounding tissue. We herein report four patients with hepatic lesions of thymomas, which were thought to have directly invaded the liver. These patients had received combined modality treatments throughout the clinical course, and the hepatic lesions appeared a long time after the initial treatment - 11.8 years on average. In these patients, the prognoses after the appearance of hepatic invasion were poor. Appropriate local control in the early stages of the clinical course may therefore be essential for preventing the extrathoracic spread of invasive thymoma.