Type B3 Thymoma : Microscopic
Type B3 thymomas have lobular architecture with coarse or delicate fibrous bands dividing the tumor into irregular lobules. At low power, the tumor has a pink appearance due to predominance of neoplastic epithelial cells arranged in solid sheets. The epithelial cells often show perivascular palisading. A small number of non-neoplastic lymphocytes, usually immature T-cells, are sprinkled in the background.