Current concepts in leptomeningeal metastasis.

Leptomeningeal metastasis is a common neurologic disorder affecting the entire neuraxis in patients with metastatic systemic cancer and primary brain tumors. The clinical presentation of leptomeningeal metastasis is pleomorphic and commonly affects the cerebral hemispheres, cranial nerves, or spinal cord and its roots. Diagnosis is confirmed by the presence of malignant cells in the cerebrospinal fluid or by clinical and neuroradiographic pattern compatible with leptomeningeal metastasis. Treatment is palliative and is directed at the entire neuraxis combining involved-field radiotherapy and intra-cerebrospinal fluid drug administration. Regional chemotherapy pharmacokinetically is best administered by intraventricular instillation employing frequent drug administration, thereby insuring prolonged cytotoxic drug exposure. Chemotherapeutic drug distribution is dependent on bulk flow of cerebrospinal fluid. This review will summarize current information regarding the incidence, clinical presentation, laboratory findings, pathology, pathophysiology, staging, treatment, and survival of patients with leptomeningeal metastasis.