Histopathologic examination of the posterior fossa mass and cerebellar hematoma using H&E staining method. (Leftmost) Sheets of malignant cells are seen invading the brain and the dura [LPO]. (Middle) Well-developed lamellated keratin pearls are appreciated [LPO]. (Rightmost) Tumor cells with pleomorphic, hyperchromatic nuclei, and prominent nucleoli [HPO].