[Neurocryptococcosis caused by nonencapsulated Cryptococcus neoformans].

The case of a patient with meningoencephafalitis due to a nonencapsulated strain of Cryptococcus neoformans is reported; he had no risk factors for the disease or AIDS. Clinical examination showed a chronic meningoencephalitis first diagnosed as tuberculosis. In the second cerebrospinal fluid (CSF) examination after a week from admission yeasts appeared inside macrophage cells. CSF culture in Sabouraud medium disclosed nonencapsulated Cryptococcus neoformans (biochemical identification). Sample inoculation in mouse (intraperitoneal) evidenced a capsule that disappeared in several consecutive cultures. The morphology of the yeast was studied by electronic microscopy. After treatment with amphotericin B and 5-fluorocytosine the patient had a favorable evolution. The significance of capsular material is discussed.