Magnetic resonance image and histopathological examination of Patient 2 showing breast cancer metastasis to the left optic nerve region. A: MRI shows one tumor mass in the optic canal surrounding the optic nerve (white circle) and another mass between the occipital lobes (white triangle). B–C: Pathological examination of metastasized cancer tissue stained with HE and immunohistochemical staining (original magnification × 200). B: Infiltrating adenocarcinoma arranged in irregular-shaped glands (HE staining). C: Thyroid transcription factor 1 (TTF-1), the marker of lung adenocarcinoma.