Brain lymphoma, sometimes called primary lymphoma of the brain, is cancer of an individual's white blood cells that starts in the brain, states MedlinePlus. As of 2015, the cause is not known, but people with weakened immune systems are more prone to develop the cancer.
Common symptoms of brain lymphoma include changes in a patient's speech or vision, confusion, hallucinations and loss of coordination, according to MedlinePlus. Performing a brain biopsy or a CT scan of the head can help diagnose the condition. Once diagnosed, treatment usually begins by administering corticosteroids to help reduce swelling around the brain. After the swelling is under control, the primary means of treating the condition is through chemotherapy, though radiation therapy is sometimes used afterwards.