PMC8077550_01
Serial MRI scans. Timeline of systemic therapies and MRI scan findings, stratified by brain lesion sites. Yellow stars denote treatment by stereotactic radiosurgery at a corresponding time point and lesion.
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F1
BMs were treated with SRS, and she was started on a phase 2 trial of niraparib plus pembrolizumab. Between December 2018 and June 2019, she received additional SRS for new lesions (Fig. 1), including a second right temporal lobe lesion just medial to the first.
Advanced MRI sequences. A Representative magnetic resonance spectra of metabolites in voxels of the right temporal lobe (top) and right cerebellum (bottom) in December 2019. B Dynamic susceptibility contrast magnetic resonance perfusion imaging of the right temporal lobe (top, hyperperfusion outlined by white arrowheads) and right cerebellum (bottom, hypoperfusion outlined by white diamonds) in April 2020.
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F2
MRI showed expansion of the peripheral enhancing lesions in the right temporal lobe and right cerebellum. MR spectroscopy in December 2019 depicted lipid abundance, favoring necrosis over tumor at both lesions (Fig. 2A). MRI with perfusion in April 2020 displayed hyperperfusion in the right temporal lobe, but not in the right cerebellum (Fig. 2B).
Histopathologic assessment of the right temporal lobe lesion. A Hematoxylin and eosin (H&E) stained specimen showing an admixture of tumor cells with astrocytic and spindled morphology (magnification, x20). B Positive immunostain for GFAP (brown), consistent with glial cells (magnification, x20). C Positive Masson trichrome stain for abundant collagen deposition (blue), a feature of sarcomatous cells (magnification, x20). D H&E stained specimen showing necrosis with viable perivascular tumor cells, more characteristic of tumor necrosis than radiation-associated necrosis (magnification, x10).
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F3
Pathology revealed gliosarcoma (IDH-wild type, MGMT promoter methylated) without evidence of metastatic carcinoma (Fig. 3).