Rare Thymoma With Solitary Liver Metastasis

Thymomas are rare, malignant, epithelial tumors of the thymus gland. Extrathoracic metastasis of thymoma is exceedingly rare, particularly when isolated to the liver. We report an 89-year-old man who presented with urinary retention. Exploratory computed tomography imaging revealed a heterogeneous mass in the aortopulmonary window and a 1.9 cm lesion in the left hepatic lobe. Results from magnetic resonance imaging, positron emission tomography-computed tomography, and histopathological analysis of biopsy samples collectively supported a diagnosis of metastatic type B2 thymoma. To the best of our knowledge, this is the oldest patient to be diagnosed with metastatic type B2 thymoma. Metastatic thymoma is difficult to identify, and patients with mediastinal mass identified after any presentation should be evaluated for malignant spread.