Source:http://linkedlifedata.com/resource/umls/id/C0205969
NCI: A malignant neoplasm of the thymus, originating from epithelial thymus cells.,NCI: A thymoma that has an aggressive clinical course (capsular invasion, infiltration of the surrounding tissues) and can metastasize. Although any morphologic subtype of thymoma may eventually have a malignant clinical course, this term is most often associated with thymoma types B3 and C.