The authors present a patient with South American blastomycosis with cerebral involvement in whom a ventriculography and a cerebral arteriography showed a tumour at the level of the fourth ventricle. After six months of therapy, clinical cure of some lesions was obtained while the neurological picture of right hemiparesia remained unchanged. Surgery was performed and the histopathological study revealed a tuberculoid, granuloma-forming gumma. The literature is reviewed and comments are made on the cerebro-spinal fluid changes and the types of involvement of the nervous system. The neurological examination and the analysis of the cerebro-spinal fluid indicated that the relative frequency of central nervous system localization in South American blastomycosis was not in agreement with current thought.