Lymphomatous meningitis (also called lymphomatous leptomeningitis) is a complication of malignant Non-Hodgkin lymphoma (NHL) caused by the spread of cancer cells from the original (primary) tumor to the meninges. The meninges are thin layers of tissue that cover and protect the central nervous system (CNS, consisting of the brain and spinal cord). Lymphoma, the most common blood cancer, occurs when immune system cells called lymphocytes, a type of white blood cell, grow and multiply uncontrollably. Cancerous lymphocytes can travel to many parts of the body including the lymph nodes, spleen, bone marrow, and blood, where they can form a tumor.1
Once lymphoma has spread by blood, local invasion extension into the meningeal space manifestations of lymphomatous meningitis occur. Spread to the meninges of NHL affects the cerebrospinal fluid (CSF, the fluid that flows in around the hollow spaces of the CNS and between two of the meninges)2,and it can produce symptoms such as pain, seizures, headache (usually associated with nausea, vomiting, and lightheadedness), walking difficulties due to weakness, memory problems, incontinence, and altered sight or hearing.2
Lymphomatous meningitis is estimated to affect approximately 7% to 15% of patients with lymphoma, although the true incidence of the disease may be higher due to under-recognition and under-reporting. Factors that increase the risk of lymphomatous meningitis include younger age, more aggressive lymphoma subtypes (Burkitts, Diffuse Large B- Cell Lymphoma), extranodal disease, increased LDH, HIV associated NHL, progressive disease/recurrence, and primary CNS lymphoma. Patients with lymphomatous meningitis have an increased risk of CNS symptoms, progression and shortened life span.
The number of patients with lymphomatous meningitis appears to be increasing, possibly because patients with lymphoma are surviving longer due to the availability of more effective cancer treatments, and the disease is most often present in lymphomas that reoccur. Also, improvements in neuroimaging studies appear to be contributing to increased rates of diagnosis of lymphomatous meningitis.2 Despite these improvements, lymphomatous meningitis is pervasively underdiagnosed and often missed until symptoms and disease characteristics have progressed. Patients with lymphomatous meningitis have a very poor prognosis, and typically survive for only a few months.3