Cryptococcal meningoencephalitis: a case report and literature review

Objective To study the clinical and pathological features of central nervous system (CNS) cryptococcosis. Methods and Results A 26-year-old male patient presented with headache and fever. Glucose, chloride and protein level was abnormal in cerebrospinal fluid (CSF) examination, but the pathogen was not found. MRI showed patchy abnormal signal at right cerebellum, the fourth ventricle and posterior horn of lateral ventricle. During the operation, cystic lesions located in right temporal lobe and grayish black choroid plexus were found, and temporal lobe lesions and degeneration of choroid plexus were partially resected. After operation, 3 pieces of greyish green tissues were resected, measuring 1.50 cm × 0.60 cm × 0.50 cm. Optical microscopic examination found a large number of birefractive oval and (or) circular cryptococcus in the brain tissue and choroid plexus, with foreign body giant cell reaction and lymphocytic infiltration. Cryptococcus could also be seen in giant cells, and spore formation was found inpart of them. Periodic acid-Schiff (PAS) and periodic acid silver methenamine (PASM) staining showed positive expression of cryptococcus. Conclusion Cryptococcosis is a common CNS fungal infection caused by cryptococcus neoformans. A large number of cryptococcus neoformans in brain tissue or lacuna is the characteristic pathological manifestation, and positive expression in PAS and PASM staining can be shown in CSF.