PMC3992747_01
Left putamen and thalamus showing hemorrhagic lesions with features of leptomeningitis
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F1
A cranial magnetic resonance imaging (MRI) [Figure 1] revealed multiple, coalescing, predominantly T1 and T2 hypointense lesions with ring enhancement located in left capsuloganglionic region, thalamus, brainstem and cortico-medullary junctions, also lesions involving left basal ganglia showed a characteristic peripheral thin rim of T1 hyperintensity with blooming on gradient-sequences and hyperdensity on plain-computed tomography (CT) scans indicative of bleed.
Multivoxel short TE MRS reveals raised choline (cho/cr-3) and lipid lactate with reduced NAA. DWI demonstrates acute infarct in left caudate head and anterior lentiform nucleus indicating occlusion of recurrent artery of Heubner due to arteritis
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F2
Magnetic resonance spectroscopy (MRS) [Figure 2] from the lesions revealed elevated lactate and choline peaks.
Large coalescing necrotizing hemorrhagic lesions are seen involving the insular cortex and putamen with extensive perilesional edema with compression of ipsilateral ventricle (a) on histology, dense vasculitis and inflammation is noted (b) large trophozoite forms with prominent nucleoli (c) is seen aggregating around vessels in addition to thick walled cyst forms of acanthamoeba (d)
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F3
At autopsy, the brain was diffusely edematous and revealed large necrotizing lesions with yellowish center surrounded by zones of hemorrhage involving parietooccipital lobes bilaterally, left orbitofrontal and inferior occipital regions [Figure 3]. At the level of optic chiasm, the left insular cortex showed large nodular confluent coalescing necrotic lesion [Figure 3] with central zones of yellowish xanthomatous areas with peripheral rim of hemorrhage [Figure 3a], extending along the sylvian fissure following the gyral pattern and superiorly into the left putamen compressing the ipsilateral ventricle. The larger leptomeningeal vessels were thrombosed with dense inflammation [Figure 3b]. Periodic acid Schiff stain highlighted several large trohphozoite form of amoeba surrounding penetrating venules and filling the Virchow Robin spaces in continuity with subarachnoid space [Figure 3c]. In addition scattered cysts morphologically resembling Acanthamoeba were detected perivascularly by silver stains [Figure 3d].
Dot blot hybridization of PCR product shows positivity in serum, brain tissue and left vitreous samples tested (arrows). The CSF and right vitreous was negative (IC: Internal positive control included in each)
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F4
Dot polymerase chain reaction for acanthamoeba was positive in serum and in vitreous of the left eye and brain tissue [Figure 4] but negative in Cerebro spinal fluid.