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. 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. 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.

中文翻译：

---

免疫受损的HIV阴性患者额叶隐球菌肉芽肿

大脑的隐球菌感染通常发生在免疫功能低下的人中，表现出提示脑膜脑炎的体征和症状。罕见的这种感染是脑肉芽肿，表现为局灶性神经功能缺损，没有明显的免疫缺陷。一名55岁男性出现吞咽困难。他的生命体征在介绍时是正常的，并且是发热的。计算机体层摄影术（CT）和核磁共振成像（磁共振成像）提示左额块肿块。考虑了隐匿性原发灶单独转移的可能性，并做了对比增强的腹部和胸部计算机断层扫描，未发现明显异常。病人进行了开颅手术并切除了病灶。切除的组织柔软，灰色且易碎。术后第5天开始发烧 并进行了脑脊液研究以排除术后细菌性脑膜炎。然而，脑脊液对隐球菌的回报为正。随后，切除组织的组织病理学报告显示隐球菌肉芽肿。他住院治疗了32天，在此期间他接受了静脉内的两性霉素B和氟胞嘧啶以及口服氟康唑的治疗。出院后，他继续口服氟康唑达47天。大脑，尤其是额叶的隐球菌肉芽肿很少见。它的临床和放射学特征类似于肿瘤形成过程。如果缺少通常呈HIV阳性状态的免疫抑制指标，则诊断可能会特别困难。这种情况需要手术干预。但是，一旦从组织学角度做出诊断，