NCIt definition : An epithelial neoplasm arising from the thymus. It may be associated with myasthenia
gravis, pure red cell aplasia, and hypogammaglobulinemia. It includes thymoma type
B1 which is a thymoma of low grade malignant potential, thymoma type B2 which is a
thymoma of moderate malignancy, and thymoma type B3 which is also known as well differentiated
thymic carcinoma.;