A diffuse intrinsic pontine glioma (DIPG) is a tumour located in the pons (middle) of the brain stem. Glioma is a general name for any tumour that arises from the supportive tissue called glia, which help keep the neurons in place and functioning well. DIPG is a brainstem glioma. The brain stem is the bottommost portion of the brain, connecting the cerebrum with the spinal cord. The majority of brain stem tumours occur in the pons and are diffusely infiltrating (they grow amidst the nerves), and therefore cannot be surgically removed. The brain stem contains all of the incoming neurons within the spinal cord, as well as important structures involved in eye movements and in face and throat muscle control and sensation.