Cryptococcal granuloma of the frontal lobe in an immunocompromised HIV-negative patient

Abstract Background Cryptococcal infection of the brain usually occurs in immunocompromised individuals and manifests with signs and symptoms suggestive of meningoencephalitis. It is rare to come across this infection as a brain granuloma manifesting with focal neurological deficits and without any overt immune deficiency. Case presentation A 55-year-old male presented with dysphasia. His vital signs were normal at presentation and he was afebrile. Computed tomography (CT) and MRI (magnetic resonance imaging) suggested left frontal mass lesion. A possibility of a solitary metastasis from an occult primary was considered and contrast-enhanced computed tomography abdomen and chest were done which revealed no significant abnormality. The patient underwent craniotomy and excision of lesion. The excised tissue was soft, greyish and friable. He started to have fever on post-operative day 5, and CSF study was done to rule out post-operative bacterial meningitis. However, the CSF returned positive for cryptococcus. Subsequently, the histopathology report from the excised tissue showed cryptococcal granuloma. He remained an inpatient for 32 days during which he received intravenous amphotericin B and flucytosine along with oral fluconazole. After discharge, he was continued on oral fluconazole for 47 days. Conclusion Cryptococcal granuloma of the brain, especially of the frontal lobe, is rare. Its clinical and radiological features mimic that of a neoplastic process. The diagnosis can be especially difficult if the usual pointer for immunosuppression in the form of HIV-positive status is missing. Such cases need operative intervention. However, once the diagnosis is made histologically, it is important to investigate for other causes of immunosuppression as in our case where the patient turned out to be deficient in natural killer cells.