| Thymoma
A neoplasm in the anterior mediastinum, originating from thymic tissue, usually benign, and frequently encapsulated; occasionally invasive, but metastases are rare; histologically, consists of any type of thymic epithelial cell as well as lymphocytes that are usually abundant. Malignant lymphoma that involves the thymus, Hodgkin's disease, should not be regarded as thymoma. | |