Fig. 1. Pathologic findings of case 2. Focal thymic carcinoma with an abundant thymoma (thymoma type B3) component. Low-power view showing a multinodular mass with extension to the peritumoral fat tissue [circle; hematoxylin-eosin stain (H-E); magnification, ×12] (A). The tumor is composed of abundant type B3 tissue (B: H-E; magnification, ×40; C: H-E, magnification, ×400) (B, C) and a focal thymic carcinoma component (squamous cell carcinoma) in the circled area (H-E; magnification, ×400) (D). Strong immunoreactivity for p63, a squamous cell differentiation marker, is found in the thymic carcinoma area (p63 immunostaining; magnification, ×400) (E). There is no p63 reactivity in the conventional thymoma B3 area (p63 immunostaining; magnification, ×400) (F).