Imaging findings of Balamuthia mandrillaris amoebic encephalitis in 2 cases with different prognosis and literature review

Abstract Introduction: Balamuthia mandrillaris amoebic encephalitis is a rare granulomatous amoeba encephalitis caused by infection with Balamuthia mandrillaris with a fatality rate over 90%. This study characterizes the imaging manifestations of Balamuthia mandrillaris amoebic encephalitis, yields critical new insights into the intracranial dissemination mechanisms of Balamuthia mandrillaris. Case presentation: We present two cases of Balamuthia mandrillaris amoebic encephalitis confirmed through Next-generation sequencing of cerebrospinal fluid and brain biopsy in our hospital, with different imaging manifestations and prognosis (One death). Meanwhile, we reviewed 16 surviving cases of Balamuthia mandrillarisamoebic encephalitis reported in literatures up to now. Conclusion: Based on 17 surviving patients imaging findings with clinical data and one death case we reported, we proposed that the key imaging features related to the prognosis of Balamuthia mandrillaris amebic encephalitis are hemorrhage within the lesion and centripetal spread through cortical and subcortical brain parenchyma into cerebrospinal fluid circulation along the meninges and ependyms. Ventriculoperitoneal shunt may be superior to ventricular drainage that could provide the patient with a chance of survival.