Invasion to and subsequent proliferation of neoplastic cells in the subarachnoid space.
This multifocal seeding of the leptomeninges by malignant cells is called leptomeningeal carcinomatosis (LC) if the primary is a solid tumor, and lymphomatous meningitis or leukemic meningitis if the primary is not a solid tumor.
The symptoms are protean and can include the following: meningeal symptoms, headaches (usually associated with nausea, vomiting, lightheadedness), gait difficulties from weakness or ataxia, memory problems, incontinence, sensory abnormalities; pain and seizures are the most common presenting complaints.
Carcinoma cells in the cerebrospinal fluid (CSF) are diagnostic, with the exception of a few false-positive results in patients who have reactive lymphocytes because of an infectious or inflammatory process in the CSF. However, negative cytologic findings do not rule out the diagnosis, as 50% of patients with LC have a negative cytologic result on the first lumbar puncture (LP). This percentage drops to 20% after second high-volume LP and 15% after third.
Treatment goals of LC include improvement or stabilization of the patient's neurologic status, prolongation of survival, and palliation.
Most patients require a combination of surgery, radiation, and chemotherapy. The standard therapies are radiation therapy to symptomatic sites and regions where imaging has demonstrated bulk disease and intrathecal chemotherapy.
For patients who are classified as poor risk, offer radiation therapy to symptomatic sites or supportive measures only (e.g., analgesics, anticonvulsants, steroids).
Treatment is difficult and primarily palliative, and results are generally poor because of the presence of many metastases.
Adapted from Medscape Drugs & Diseases. Leptomeningeal carcinomatosis. Available at http://emedicine.medscape.com/article/1156338-overview. Accessed on February 15, 2016. To view the entire article and all other content on the Medscape Drugs & Diseases site, a free, one-time registration is required.