1. B C * C * A A B
MRI showing the reassessement of the brain metastasis during ICI. (A) Hematoxylin-phloxine-saffron (HPS) stained specimen of the lesion on Gd-MRI of the same patient . The histological correlate to the MRI solid component typically shows an invasive adenocarcinoma (↑) while large areas of necrosis (↑↑) lead to the cystic component (bar =500 μm). The tumor extends to the meninges (*). (B) The higher magnification demonstrates sheets of large epithelial tumor cells with irregular nuclei, numerous mitosis (↑) and necrosis (↑↑) (bar = 50 μm). (C) Tumor cells infiltrate the cortex closely aligned to the external surface of blood vessels (*). (bar = 50 μm). *