Neoplastic Meningitis AKA Meningitis Carcinomatosa AKA Leptomeningeal Carcinomatosis
#Consider this diagnosis in the patient with known oncologic history and new neurologic deficits
#Patients with leptomeningeal disease associated with malignancy may present with symptoms consistent with aseptic meningitis such as headache and nausea/vomiting but remember that they may also be free of meningismus and instead may present with multiple new neurologic deficits that are hard to localize to one lesion, for example, leg weakness and a cranial nerve palsy.
#Large cell lymphomas and leukemias can cause neoplastic meningitis but solid tumors can cause it as well. Solid tumors that have been associated with leptomeningeal involvement include melanoma, lung cancer, and breast cancer.
#The diagnosis can be made by observing intradural nodules or a characteristic nerve root thickening/enhancement on gadolinium-enhanced MR or by LP which could reveal eosinophilia elevated protein, lymphocytic pleocytosis, or malignant cells on cytology.
#Infectious causes of meningitis which can cause similar presentations include: cryptococcal infection, coccidioidal infection, TB, lyme disease, syphilis, and ehrlichiosis.