Medulloblastoma is a type of brain tumor that primarily affects children, although it can occur in adults. It originates in the cerebellum, the part of the brain responsible for coordination and balance. This tumor is classified as a primitive neuroectodermal tumor (PNET) and can spread to other parts of the central nervous system. Symptoms of medulloblastoma may include headaches, nausea, vomiting, and problems with balance or coordination. Diagnosis typically involves imaging tests like MRI and may require a biopsy. Treatment often includes surgery, radiation therapy, and chemotherapy to target and eliminate the tumor cells.