The exhibit displays a well encapsulated lesion. It composed of lobules separated by thin septae. It shows homogenous brown surface.

Type AB thymoma is composed of a lymphocytes-poor type A component and a lymphocytes rich type B-like component. Type A component is composed of spindly or oval shaped, bland nuclei cells with low mitotic activity and only few immature lymphocytes. Type B-like component is composed of prominent infiltrates of immature lymphocytes with small and oval neoplastic cells exhibit dispersed chromatin and inconspicuous nucleoli.

Thymoma-Type AB

Name other type of thymoma : A, B1, B2, B3,metaplastic thymoma, microscopic thymoma, sclerosing thymoma, lipofibroadenoma.