There is a predominance of large, polygonal, epithelial cells characterized by open nuclear chromatin and ample cytoplasm. Only a few lymphocytes are scattered in between the epithelial cells. In the center of the picture there is a vessel with perivascular space with scattered and clustered lymphocytes, a common finding specifically in type B3 thymomas. H&E, magnification × 400.
WHO: World Health Organization; H&E: hematoxylin and eosin.