Communicating hydrocephalus in treated leukemic patients.

7 brains out of a series of 124 necropsies of treated leukemic patients show a communicating hydrocephalus, without invasion of the central nervous system by the malignant blood cells. In 4 cases it is proven that the hydrocephalus is due to obstruction of the liquor drainage at the level of the arachnoidal villi and dural sinuses, by the leukemic invasion of these structures. It is shown that, even in case of preventive brain irradiation and intrathecal-administered cytotoxic drugs, these structures remain areas, in which the leukemic cells are difficult to destroy.