PMC9813211_01
Tumor showing piloid morphology with regularly interspersed dysplastic neurons (H&E 100x).
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F1
Histology demonstrated cells with piloid morphology with regularly interspersed dysplastic neurons (see Figure 1).
Immunohistochemistry performed on tumor demonstrating absence of IDH R132H expression (40x), positive neurofilament NF52 (40x) and less frequent CD34 (100x) expression in tumour as well as BRAF V600E (40x) expression in tumour cells.
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F2
CD34 labeled tumor cells only and IDH staining was negative (see Figure 2).
Axial T1 MRI images ganglioglioma pre-BRAF therapy (A) and 4 months post-BRAF therapy (B).
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F3
Further neuroimaging 4 months post-commencement of BRAF-targeted therapy demonstrated a significant reduction in the size of the right cerebral mass lesion consistent with partial response to BRAF-targeted therapy (see Figure 3).
PMC9813211_02
(A) (H&E, 20x) Fibrous type tissue with lymphocytic infiltration and vacuolated histiocytes; (B) (H&E, 40x) Vacuolated cells showing emperipolesis.
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F4
The cells within nodules were cytoplasm rich with occasional large hypochromatic nuclei and demonstrated emperipolesis (see Figure 4).
Axial T1 post-contrast MRI images Rosai-Dorfman disease pre-BRAF therapy (A) and 3 months post-BRAF therapy (B).
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F5
Interval MRI of the brain was performed 4 months post-commencement of BRAF/MEK inhibitor therapy, which demonstrated treatment response (see Figure 5).
PMC9813211_03
Axial T1 MRI images ganglioglioma pre-BRAF therapy (A) and 3 months post-BRAF therapy (B).
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F6
MEK inhibitor binimetinib. MRI of the brain 3 months post-initiation of BRAF-targeted therapy demonstrated interval reduction in the size of the cystic tumor lesions in the right basal ganglia and midbrain suggestive of treatment response (see Figure 6).