A primary central nervous system lymphoma is a rare cancerous tumor that develops from cells in the central nervous system, which consists of the brain, eyes and spinal cord. The cancer may also be described as a primary CNS lymphoma, or PCNSL, for short. A primary tumor is one which originated in the place where it is growing, while a secondary tumor is one which has spread from somewhere else, so a primary CNS lymphoma is thought to develop from nerve cells in the central nervous system. It is not fully understood how this occurs, as lymphomas normally develop from lymph tissue, which forms part of the immune system and is not found in the central nervous system. Although primary central nervous system lymphoma is rare, it is becoming more commonly seen in people who have immunosuppression, where the immune system is weak, due to illnesses such as AIDS or following an organ transplant.
The symptoms of a primary central nervous system lymphoma are mostly due to a rise in pressure inside the skull. This may be caused by a blockage in the flow of fluid that surrounds the brain or directly by the growing tumor mass. A pressure increase can lead to visual problems, headaches and vomiting. Other symptoms caused by the tumor may include increasing confusion and seizures. If certain areas of the brain are affected by the lymphoma, problems with balance and coordination may develop and occasionally one side of the body may become weak.
Most often, a primary central nervous system lymphoma is what is known as a high-grade non-Hodgkin lymphoma, which means that it tends to grow quickly and is more likely to spread than a low-grade tumor. Treatment for the primary intracranial tumor varies according to the location and size of the lymphoma, and whether it has already spread. A person who is otherwise healthy may require different treatment from someone who is immunosuppressed. There is no single best treatment option, but chemotherapy may be used, sometimes in combination with radiotherapy, and steroids may lower the pressure inside the skull by reducing swelling and tumor size.
The outlook for someone with a primary central nervous system lymphoma varies according to the individual and the type of treatment which is received, but long-term survival is uncommon. Generally, there is a 50 percent chance of surviving for longer than two years. Younger patients who are in better overall health have a more positive prognosis.