Amoebic encephalitis

Case contributed by Dr Matthew Lukies


Past history of aplastic anaemia, bone marrow transplantation and curatively resected gastric cancer (T1N0M0) presented with headache, fever and impaired consciousness.

Patient Data

Age: 52
Gender: Male

On T2 weighted images two pseudotumoural masses are seen in the left parietal and occipital lobes with low signal rim surrounding. T2* shows low signal around masses indicating hemorrhagic change.

Case Discussion

Postmortem histopathology confirmed the diagnosis of amoebic encephalitis from Acanthamoeba spp.

Amoebic encephalitis is a rare and usually fatal disease that occurs almost exclusively in patients with immunosuppression. Amoebae including Acanthamoeba sppBalamuthia mandrillaris, Naegleria fowleri and Sappinia pedata have all caused encephalitis in reported cases worldwide. There are currently no effective treatments.

Imaging findings are nonspecific and rarely described in literature, but can include:

  • —multiple parenchymal lesions
  • —pseudotumoural lesions
  • —meningeal exudates
  • —hemorrhagic infarcts
  • —necrosis


Images and case thanks to Osaka University Hospital

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Case information

rID: 35773
Published: 27th Apr 2015
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included

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