Cryptococcal infections of the central nervous system are very rare in immunocompetent patients. They usually present as meningitis or as fungal cysts with or without hydrocephalus. Rapid diagnosis and treatment is crucial to the prognosis.

We report the case of an immunocompetent 40-year-old male patient with no medical or surgical history and no recent travel, who was hospitalized in our neurosurgery department because of a rapidly worsening headache. The neurological examination revealed no focal deficit but worrying signs of increased intracranial pressure. Magnetic resonance imaging (MRI) with contrast showed thick and large-scale cortico-pial cerebellar enhancements, associated with severe obstructive hydrocephalus. This required emergency endoscopic ventriculocisternostomy during which we observed cottony tissues along the ventricular walls. Biopsied tissues and cerebrospinal fluid samples (CSF) were not contributive. A CT scan of the chest and abdomen and blood markers of common primary tumors were all negative. No evidence of HIV infection or any cause of immunosuppression was identified. Symptoms and a second MRI slightly improved with intravenous corticosteroid therapy. The hypothesis of a lymphoma or granulomatous disease was made initially for which direct surgical biopsies were scheduled. The diagnosis of cryptococcal meningitis was obtained later on by simultaneous plasma and CSF Cryptococcus antigen detection. Cryptococcus neoformans (formerly C. neoformans var. grubii [serotype A]) was then identified by PCR. Clinical improvement was obtained with antifungal therapy.

Cryptococcal meningitis is a well-known condition in immunocompromised patients, often causing hydrocephalus requiring neurosurgical management. The diagnosis is more difficult in patients with no history of HIV or organ transplant. Neurologists and neurosurgeons must consider this possibility in case of diffuse, thick leptomeningeal enhancement on MRI.