Leptomeningeal cancer

Neoplastic meningitis
Other names	Carcinomatous meningitis, leptomeningeal carcinoma, leptomeningeal carcinomatosis, leptomeningeal metastasis, meningeal carcinomatosis, meningeal metastasis, meningitis carcinomatosa, leptomeningeal disease (LMD), neoplastic meningitis
Meningeal carcinomatosis: tumor cell clusters in the subarachnoid space in a brain biopsy
Specialty	Oncology, neurology

Leptomeningeal cancer is a rare complication of cancer in which the disease spreads from the original tumor site to the meninges surrounding the brain and spinal cord.^[1] This leads to an inflammatory response, hence the alternative names neoplastic meningitis (NM), malignant meningitis, or carcinomatous meningitis.^[2][3] The term leptomeningeal (from the Greek lepto, meaning 'fine' or 'slight') describes the thin meninges, the arachnoid and the pia mater, between which the cerebrospinal fluid is located.^[4] The disorder was originally reported by Eberth in 1870.^[5] It is also known as leptomeningeal carcinomatosis, leptomeningeal disease (LMD), leptomeningeal metastasis, meningeal metastasis and meningeal carcinomatosis.

It occurs with cancers that are most likely to spread to the central nervous system.^[6] The most common cancers to include the leptomeninges are breast cancer, lung cancer, and melanomas because they can metastasize to the subarachnoid space^[7] in the brain which offers a hospitable environment for the growth of metastatic tumor cells.^[7][8] Individuals whose cancer has spread to an area of the brain known as the posterior fossa have a greater risk of developing a leptomeningeal cancer.^[9] The condition can also arise from primary brain tumor like medulloblastoma.

Leptomeningeal disease is becoming more evident because cancer patients are living longer and many chemotherapies cannot reach sufficient concentrations in the spinal fluid to kill the tumor cells.^[7]