Non-granulomatous cerebellar infection by Acanthamoeba spp. in an immunocompetent host
Acanthamoeba spp. is a free-living amoeba, frequently involved in keratitis by contact lens in immunocompetent hosts. Anecdotal reports associate Acanthamoeba spp. as a cause of severe granulomatous encephalitis in immunocompromised and, less frequently, in immunocompetent subjects. Data regarding clinical and therapeutic management are scanty and no defined therapeutic guidelines are available. We describe an unusual case of non-granulomatous Acanthamoeba cerebellitis in an immunocompetent adult male, with abrupt onset of neurological impairment, subtle hemorrhagic infarction at magnetic resonance imaging, and initial suspicion of cerebellar neoplasm. Histopathological findings of excised cerebellar mass revealed the presence of necrosis and inflammation with structure resembling amoebic trophozoites, but without granulomas. Polymerase chain reaction from cerebellar tissue was positive for Acanthamoeba T4 genotype. Due to gastrointestinal intolerance to miltefosine, the patient was treated with long-term course of fluconazole and trimethoprim/sulphamethoxazole, obtaining complete clinical and neuroradiological resolution.
KeywordsAcanthamoeba Free-living amoebas Encephalitis Immunocompetent host
We thank Marguerite Kelly Keating, formerly Infectious Disease Pathology Branch, Centers for Disease Control and Prevention (CDC), for critical revision of the manuscript.
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Conflict of interest
SM, CM, MGC, GC, VFM, FI, CN, IKMA, SR, AC, GZ: no conflict. ADL reports research grants to his Institutions by ViiV Healthcare, Gilead Sciences (fellowship program) and MSD Italy; he has received consultant fees from ViiV Healthcare, Gilead Sciences, MSD Italy, Janssen, Bristol-Myers Squibb and Abbvie; all outside the submitted work. FM has received non-financial support from Angelini and Astellas, outside the submitted work. She has done contract research for Novartis Vaccine and Diagnostic S.rl. (now GSK Vaccine S.r.l.) on behalf of the University Hospital of Siena; she is Infectious Diseases Consultant for GSK (consultancy fee on behalf of University of Siena).
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