This MICCAI Challenges proceedings book includes contributions from the BraTS 2025 Lighthouse Challenge focusing on brain tumor image analysis, including longitudinal assessment of brain tumor response, generalizability of tumor segmentation methods across different entities, and inclusion of tumor entities for which there is currently limited annotated data. It also contains contributions from the AIMS-TBI 2025 Challenge that deals with the detection and segmentation of lesions in T1-weighted MRI data from moderate-severe traumatic brain injury. The 79 papers included in the proceedings were carefully reviewed and selected from a total of 90 submissions. The papers were organized in topical sectios as follows: Part I: Invited Paper.- Challenge 1 - BraTS-GLI Challenge; Challenge 2 - BraTS-MEN; Challenge 3 - BraTS-MEN-RT; Challenge 4 - BraTS-METS; Challenge 5 - BraTS-Africa; Challenge 6 - BraTS-PED; Challenge 7 - BraTS-GOAT; Part II: Challenge 8 - BraTS-Synth; Challenge 9 - BraTS-Inpainting; Challenge 10 - BraTS-Path; Challenge 11 - BraTS-PRO; Challenge 12 - AIMS-TBI.