Leptomeningeal metastases

Metastases to the nervous system are an increasingly common complication of cancer, and can involve the brain parenchyma, dura, skull, epidural space, peripheral nerves, and leptomeninges (pia and arachnoid membranes). Leptomeningeal metastasis (LM) is defined as the appearance of tumor cells in the leptomeninges or cerebrospinal fluid (CSF) distant from the site of a primary tumor [1]. LM is also know as carcinomatous meningitis, neoplastic meningitis, neoplastic meningosis, leukemic meningitis (for leukemia), lymphomatous meningitis (for lymphoma), and meningeal carcinomatosis (for carcinoma) [2-11]. LM was first described in 1870 in a patient with lung cancer, and was thought to be a rare condition, usually diagnosed at autopsy [12]. By the 1970s, the condition was increasingly diagnosed due to increased suspicion and improved diagnostic tests [8,13]. As treatments for systemic cancers improve and as patients live longer, there is a higher risk of central nervous system (CNS) metastases, including LM. LM has a devastating impact on the prognosis and quality of life for affected patients. Neurologic dysfunction may severely impair the ability of a patient to function independently. Advances in diagnostics, chemotherapy, radiotherapy, and surgery have made it possible to partially alleviate symptoms and to improve the quality of life. Further advances in modalities that may allow earlier diagnosis of LM and the development of more effective therapeutics may offer future patients with LM an improved quality of life and longer duration of survival.