the ubiquity of cells of the monocyte-histiocyte series allows six possibilities of cns involvement : a ) primary in the brain : b ) secondarily involve the brain or spinal cord by extending from a cranial bone or vertebra to the epidural space c ) rarely to involve intraneuronal tissues ( lymph nodes , bone , viscera ) and then later to localize to the brain substance d ) to spread from brain outside the nervous system e ) to evoke any one or several of the paraneoplastic diseases ( polymyositis , polyneuritis , cerebellar degeneration , f ) to permit widespread infections of the nervous system such as multifocal leucoencephalitis .
C0037303
cranial bone
C0006104
brain