PEDIATRIC LEPTOMENINGEAL METASTASIS - IN-111 DTPA CEREBROSPINAL-FLUID FLOW STUDIES

Nine children (five girls and four boys) ranging in age from 1 to 18 years (median age, 12 years) with leptomeningeal metastasis were evaluated for cerebrospinal fluid compartmentalization with cerebrospinal fluid flow studies using ventricular diethylenetriaminepentaacetic acid labeled with indium 111 (In-111-DTPA). Histologic diagnosis included medulloblastoma (two), primitive neuroectodermal tumor (two), acute lymphoblastic leukemia (two), pineoblastoma (one), ependymoma (one), and anaplastic astrocytoma (one). Sixteen In-111-DTPA cerebrospinal fluid flow studies were performed, of which nine demonstrated normal anterograde cerebrospinal fluid flow of radionuclide, with the following cerebrospinal fluid compartment median times to appearance, with ranges in parentheses: ventricles, 1 minute (0 to 3 minutes); cisterna magna/basal cisterns, 5 minutes (3 to 5 minutes); cervical subarachnoid space, 8 minutes (5 to 10 minutes); thoracic subarachnoid space, 15 minutes (10 to 30 minutes); lumbar subarachnoid space, 35 minutes (20 to 45 minutes); and sylvian cistern, 80 minutes (60 to 90 minutes). Blockage of normal anterograde cerebrospinal fluid flow was seen in seven In-111-DTPA cerebrospinal fluid flow studies in the following cerebrospinal fluid compartments: cervical subarachnoid space (four), lumbar subarachnoid space (two), and cisterns magna/basal cisterns (one). Five In-111-DTPA cerebrospinal fluid flow studies were performed after demonstration of cerebrospinal fluid compartmentalization and treatment with limited-field radiation therapy to involved regions; cerebrospinal fluid flow blocks resolved in three. In conclusion, cerebrospinal fluid compartmentalization, as shown by radionuclide ventriculography, is a common occurrence in pediatric leptomeningeal metastasis (four of nine patients, or 44%) and may be palliated by involved-field radiotherapy.