Primary intracranial malignant lymphomas a fine structural cytochemical and CSF immunological study.

Cytochemical and electron microscopical studies in six cases of primary intracranial malignant lymphomas, four of which were diagnosed by biopsy, confirmed their ultrastructural identity with extraneural malignant lymphomas classified as immunoblastomas and immunocytomas. Demonstration of transformation of 'blast-like' cells (immunoblasts) toward rough E. R. developing cells in all these tumours argue for the B-dell origin of these types of cerebral lymphomas, previously referred to as reticulum cell sarcomas/microgliomas. CSF studies showed increased levels of B cells with surface IgG in two cases of immunoblastoma, and increased IgG levels with light chains in two cases each immunoblastoma and of pleomorphic immunocytoma, while one case of immunoblastoma showed a normal T cell to B cell ratio with increased monoclonal and surface, IgM suggesting some morphological and immunological heterogeneity of these lymphomas.