Spinal meningeal uptake of technetium-99m methylene diphosphonate in meningeal seeding by malignant lymphoma.

Definite diagnosis of meningeal seeding by systemic cancer relies on the presence of malignant cells in the cerebrospinal fluid (CSF). In the absence of such cells in the CSF, only two other tests strongly suggest the diagnosis--a CT scan and a myelogram. We report a case in which the diagnosis was strongly suggested by an unusual uptake of Tc-99m methylene diphosphonate by the leptomeninges during a skeletal scan and later established by the presence of malignant cells in the CSF. We believe that radionuclide scan may be an additional diagnostic test in some cases with meningeal seeding by systemic cancer. We therefore are extending our studies to validate this possibility.