Certain notable clinical attributes of the histiocytic sarcomas of the central nervous system

By the term reticulum cell sarcoma we denote any tumor composed predominantly of undifferentiated cells, some of which have the qualities of histiocytes. The origin of such CNS tumors may be traced to circulating monocytes, perithelial ro meningeal histiocytes or microgliocytes. 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. Clinical attributes to be emphasized are the relative rarity of hematogenous metastases (2 of 121 cases), the relatively high incidence of such tumors in immunologically suppressed individuals (12 of 5000 cases), the frequency of primary tumors of CNS (23 of 144 cases), the high incidence of epidural and dural involvement from osseous lesions (13 of 121 cases); the rapid evolution of clinical phenomena; the rarity of paraneoplastic syndromes; the occasional spontaneous and frequent therapeutic regression upon x-radiation. The common invasion of pia and ependyma by the tumor cells and their natural tendency to phagocytosis opens unrealized possibilities of clinical diagnosis by cytological examination and culture of CSF. Early diagnosis by these methods permits avoidance of surgery and the use of radiation and possibly chemotherapy, which may be rewarded by symptomatic regression and potential cure.