A review of leptomeningeal metastases in pediatrics.

Leptomeningeal metastasis is an uncommon problem in pediatric neurology and oncology. It occurs primarily in children with acute lymphoblastic leukemia and primary brain tumors. Although leptomeningeal metastasis may present with focal neurologic signs and symptoms, leptomeningeal metastasis is a disease affecting the entire neuraxis and necessitating an extent-of-disease evaluation of both the brain and spinal cord. Neuroradiographic staging of leptomeningeal metastases includes contrast-enhanced cranial computed tomography, magnetic resonance imaging, contrast-enhanced spine magnetic resonance imaging or computed tomographic myelography, and radionuclide cerebrospinal fluid flow studies. As a consequence of global neuraxis involvement, the treatment of leptomeningeal metastases requires therapy directed at all cerebrospinal fluid compartments. The treatment of leptomeningeal metastases usually includes both radiotherapy and intra-cerebrospinal fluid drug therapy. Radiotherapy is directed to regions of bulky or symptomatic central nervous system disease. Intra-cerebrospinal fluid drug therapy, using one of three available chemotherapeutic agents (methotrexate, cytarabine, or triethylene thiophosphoramide), is administered by a variety of schedules and either by intralumbar or intraventricular drug delivery. Notwithstanding that the treatment of leptomeningeal metastases is palliative, with an expected patient survival of 6 months, it often affords stabilization and protection from further neurologic deterioration in children with leptomeningeal metastases in whom death is usually a consequence of progressive systemic or parenchymal brain disease.