Balamuthia颗粒状变态反应性阿米巴性脑膜脑炎(GAE)是一种中枢神经系统的奇特寄生虫感染疾病，大约39％的感染Balamuthia GAE患者被发现免疫系统受损，并且在临床上极为罕见。在患病组织中存在滋养体是GAE病理诊断的重要依据。Balamuthia GAE是一种罕见且高度致命的感染病，目前在临床实践中没有有效的治疗计划。本文报道了一例Balamuthia GAE患者的临床数据，旨在提高医生对该病的了解和影像诊断准确性，并减少误诊。一名61岁的家禽养殖工人有三周前右前囟区中等肿胀疼痛，头部计算机断层扫描(CT)和磁共振成像(MRI)显示右侧额叶有占位性病变。最初的临床影像诊断为高级别星形胶质母细胞瘤。病变的病理诊断为炎性肉芽肿性病变，并伴有大量坏死，提示出现了阿米巴感染。通过元基因组下一代测序(mNGS)检测到的病原体为Balamuthia mandrillaris，并最终病理诊断为Balamuthia GAE。当头部磁共振成像显示不规则或环形强化时，临床医生不应盲目诊断脑肿瘤等常见疾病。虽然Balamuthia GAE仅占颅内感染的一小部分，但应列为鉴别诊断的考虑之一。© 2023作者。

Balamuthia granulomatous amoebic encephalitis (GAE) is a peculiar parasitic infectious disease of the central nervous system, about 39% of the infected Balamuthia GAE patients were found to be immunocompromised and is extremely rare clinically. The presence of trophozoites in diseased tissue is an important basis for pathological diagnosis of GAE. Balamuthia GAE is a rare and highly fatal infection for which there is no effective treatment plan in clinical practice.This paper reports clinical data from a patient with Balamuthia GAE to improve physician understanding of the disease and diagnostic accuracy of imaging and reduce misdiagnosis. A 61-year-old male poultry farmer presented with moderate swelling pain in the right frontoparietal region without obvious inducement three weeks ago. Head computed tomography(CT) and magnetic resonance imaging(MRI) revealed a space-occupying lesion in the right frontal lobe. Intially clinical imaging diagnosed it as a high-grade astrocytoma. The pathological diagnosis of the lesion was inflammatory granulomatous lesions with extensive necrosis, suggesting amoeba infection. The pathogen detected by metagenomic next-generation sequencing (mNGS) is Balamuthia mandrillaris, the final pathological diagnosis was Balamuthia GAE.When a head MRI shows irregular or annular enhancement, clinicians should not blindly diagnose common diseases such as brain tumors. Although Balamuthia GAE accounts for only a small proportion of intracranial infections, it should be considered in the differential diagnosis.© 2023. The Author(s).