[Light and electron microscopic observations of cysts in the brain from an autopsy case of cryptococcus meningitis].

We gave some considerations to the significance of cyst formation in a case of cryptococcus meningitis by examining the cysts themselves and comparing the organisms in the cysts with those disseminated throughout the subarachnoid space by light and electron microscopy. An 18-year-old girl had complained of headache, stiffneck and fever at the onset. These symptoms worsened into confusion without any definite diagnosis, then resulted in an arrest of spontaneous respiration which led to use of respirator for 12 days. The patient died 40 days after the onset. The brain weighed 1440 g and showed moderate swelling with opacity of the leptomeninges, which was very evident over the convexity and around the basal side of the pons. Subarachnoid fresh hemorrhage was also observed around the basal side of the brain stem. Microscopic examination of the subarachnoid space revealed widely disseminated Cryptococcus neoformans varied in size, whose cell wall showed a positive staining reaction to PAS. The organisms had characteristic spicules positively stained with cresyl violet radiating out of the cell body, and were associated with infiltration of lymphocytes, macrophages and polymorphonuclear leukocytes throughout the subarachnoid space. Some portions of arachnoid membrane, dura mater and vessel walls in the subarachnoid space especially the adventitia of the basilar artery were replaced by multiple cysts. The cysts were tightly filled with large numbers of small uniformly sized organisms which often showed budding. These cysts showed no histological evidence for inflammation. Further studies to demonstrate those differences were carried out with electron microscopy.(ABSTRACT TRUNCATED AT 250 WORDS)