PMC6900946_01
Timeline of the case report.
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His past medical history was unremarkable, and there was no significant family history or any occupational exposure potentially associated with sarcoma.  Figure 1 provides a timeline of events including diagnostic assessments and interventions.
The progression of astrocytoma and development of dural-based nodules. (a-d) Images of axial MRI: a 2.4 x 2.5 cm mass in the right lateral to midtemporal lobe and associated area of hemorrhage at initial presentation (a), a growing nodule of contrast enhancement in the right frontal lobe at 5 months after completion of RT (b), follow-up 1 after 6 cycles of bevacizumab (c), and an increase in dural-based nodules involving the entire right hemisphere and the left cerebellum as well as an increase in size of the centrally necrotic mass in the right frontal lobe at follow-up 2 of dural-based nodules (d). White arrows indicate new dural-based nodular areas of enhancement. (e-h) Images of MRI perfusion: at initial presentation (e), at 5 months after completion of RT (f), at follow-up 1 after 6 cycles of bevacizumab (g), and at follow-up 2 of dural-based nodules (h). (i-k) Representative images of H&E staining: an initial Grade II Astrocytoma at high and low (inset) power (i), dural nodule showing increased mitotic activity at high and low (inset) power (k), and Grade III Astrocytoma at high and low (inset) power after second tumor resection (j).
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Computed tomography (CT) and magnetic resonance imaging (MRI) of the brain demonstrated a 2.4 x 2.5 cm mass in the right lateral to midtemporal lobe and associated area of hemorrhage (Figures 2(a) and 2(e)). Pathologic review identified a WHO Grade II Astrocytoma (Figure 2(i)). MRI at 4 and 5 months after completion of RT showed a growing nodule of contrast enhancement in the right frontal lobe and associated vasogenic edema despite dexamethasone treatment (Figure 2(b)). MRI perfusion studies showed increased blood flow to these new areas (Figure 2(f)), and a second tumor resection was performed. Pathologic assessment revealed a mixture of radiation necrosis and WHO Grade III Astrocytoma (Figure 2(j)) with no isocitrate dehydrogenase (IDH) mutation. However, a follow-up MRI showed increased enhancement of the right frontal lobe mass and new dural-based nodular areas of enhancement (Figure 2(c)). As expected, there was reduced cerebral blood flow observed on MRI perfusion; however, the increased enhancement was concerning as this is typically reduced with bevacizumab treatment (Figure 2(g)). A biopsy of a right frontal dural-based nodule was pursued, and the pathologic assessment was consistent with a high-grade sarcoma lacking any further differentiating features (Figures 2(k) and 3(a)-3(c)). Follow-up MRI revealed an increase in dural-based nodules involving the entire right hemisphere and left cerebellum, as well as an increase in size of the centrally necrotic mass in the right frontal lobe (Figures 2(d) and 2(h)).