PMC4813065_01
FLAIR axial image showing two well-defined focal mass lesions in the right temporal and occipital lobes (A and B). DWI showing restriction of diffusion in the wall of the lesions in the right temporal/occipital lobe (C and D)
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T2-weighted coronal images and fluid-attenuated inversion recovery (FLAIR) axial images revealed two well-defined focal mass lesions in the right postero-medial temporal lobe and occipital lobe without any perilesional edema [Figure 1A and B]. Diffusion-weighted images (DWI) revealed no significant restriction of diffusion in the mass lesions [Figure 1C and D].
(A-C) Post-contrast T1 sagittal image shows heterogeneous enhancement of lesions in the right temporal and occipital lobes (A and B). Multivoxel intermediate TE MR spectroscopywith mild elevation of choline in mass lesions, with choline to creatine ratio range is 1.3-1.9 (C)
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Post-contrast study revealed heterogeneous enhancement in the lesions [Figure 2A and B]. MR spectroscopy revealed mild elevation of choline in the lesions, with choline to creatinine ratio in the range of 1.3-1.9 [Figure 2C].
FLAIR and T2W images show multiple focal hyperintensities in bilateral hippocampi, dorsal thalami, and cingulate gyri (A and B), no enhancement was seen on post-contrast study in hippocampi and affected cortices (C and D). Multivoxel intermediate TE MR spectroscopy shows normal choline peak (E)
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Also noted were multiple focal asymmetrical areas of altered signal intensities in bilateral hippocampi, dorsal thalami, and cingulate gyri [Figure 3A and B]. There was no abnormal enhancement on post-contrast study [Figure 3C and D].
PET CT showing avid FDG uptake in intracranial masses and no abnormal FDG avid activity in the rest of the body (A and B)
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Subsequently, patient underwent whole-body positron emission tomography (PET) study which revealed focal fluorodeoxyglucose (FDG) avidity only in two intracranial mass lesions detected on MRI in the right temporo-occipital lobes without any FDG avid lesion in the rest of the body [Figure 4A and B].
200x H and E and immunohistochemistry slide shows multiple neoplastic astrocytes with high mitotic index (A-D). 200x H and E slide shows reactive gliosis with interstitial and perivascular infiltrates of lymphocytes, a feature of paraneoplastic encephalitis (D)
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Mass lesion histopathology revealed pleomorphic astrocytes with interspersed proliferated blood vessels having heaped up endothelial cells (glomeruloid structures) [Figure 5A]. Ki67 immunohistochemistry showed proliferation index of 30% [Figure 5B]. Immunohistochemistry also showed glial fibrillary acidic protein (GFAP) positivity in the tumor cells [Figure 5C]. Biopsy of cortical area showing non-neoplastic signal abnormality revealed reactive gliosis with interstitial and perivascular infiltrates of lymphocytes, a feature of paraneoplastic encephalitis [Figure 5D].
FLAIR axial and T2W coronal images in follow-up MRI done after 6 months reveal significant decrease in cortical hyperintensity in bilateral cigulate gyri when compared with preoperative initial MRI images (C and D)
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