Disseminated cerebral cryptococcosis after silent West Nile virus infection in a patient with polycythemia vera: A case report and review of the literature.

Although disseminated cryptococcosis can occur occasionally, it is most commonly seen in immunodeficient patients. In 2005, a 43-year-old man was diagnosed with polycythemia vera. Following in 2018, he experienced an unknown-cause fever and headache. To establish the source of the symptoms, a magnetic resonance imaging scan of the brain was performed, which indicated meningeal and gyral-leptomeningeal thickening and several localized T2 hyperintense lesions measuring up to 10 × 14 mm in diameter. Cryptococcus neoformans was then cultivated from cerebrospinal fluid. Serum IgM antibodies against West Nile Virus were positive. After 8 weeks of treatment with amphotericin B and fluconazole, the overall condition improved, and the cerebrospinal fluid control culture became negative. The symptoms returned shortly after discontinuing antifungal therapy, necessitating the reintroduction of fluconazole. Currently, the patient is stable and responding positively to ruxolitinib. Here, it is demonstrated how a patient with polycythemia vera due to immunological weakness might develop disseminated cryptococcosis of the brain after West Nile virus infection.