Cerebral distribution of immunoconjugate after treatment for neoplastic meningitis using an intrathecal radiolabeled monoclonal antibody.

A detailed autopsy and autoradiographic study was performed after the death of a patient undergoing intrathecal, antibody-guided irradiation for carcinomatous meningitis. The results demonstrated tumor cells infiltrating the surface meninges and a severe astrocytic reaction associated with oedema in the periventricular and brain stem subpial white matter. This was not seen in cortical or other gray matter structures. Autoradiographic examination correlated well, demonstrating isotope within the oedematous areas of the white matter in addition to the expected concentration in the leptomeningeal layers. These findings are discussed in the context of antibody binding to tumor tissue and the possible benefits conferred in the treatment of infiltrating tumor cells.