PMC4900105_01
57-year-old female with a midline cerebellar pilocytic astrocytoma with anaplastic features. Conventional MRI T2-weighted scans show a solid and cystic cerebellar mass with surrounding edema on two contiguous slices (A, B).
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T2-weighted MRI (Figs. 1A, 1B), which had increased in size from prior studies.
57-year-old female with a midline cerebellar pilocytic astrocytoma with anaplastic features. Diffusion tensor axial (A) and coronal (B) tractography in this patient demonstrates displaced but intact cerebellar fiber tracts surrounding the lesion.
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Tractography (Figs. 2A, 2B) and FA maps (Fig. 3) suggested on the basis of imaging that fiber tracts surrounding the lesion were displaced, but fiber integrity (as represented by fractional anisotropy) was maintained. This suggested a less aggressive type of neoplastic lesion.
57-year-old female with a midline cerebellar pilocytic astrocytoma with anaplastic features. Tumor histology in patient shows features (arrows). A. Dense and loose zones with microcysts. B. Rosenthal fibers and hemosiderin. C. Eosinophilic granular bodies. D. Microcalcifications.
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The histopathology showed a largely circumscribed astrocytoma with associated macrocysts, microcalcifications, eosinophilic granular bodies, and rare Rosenthal fibers, consistent with a benign entity such as a pilocytic astrocytoma (PA) (Fig. 4).
57-year-old female with a midline cerebellar pilocytic astrocytoma with anaplastic features. Tumor histology in patient shows anaplastic features (arrows). A. Mitotic figures. B. Vascular proliferation. C. Nonpalisading necrosis. D. Necrosis with a pseudopalisade.
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However, focally localized atypical features were also present, including a hypercellular focus with increased mitotic activity and pseudopalisading necrosis, and vascular proliferation, consistent with PA with anaplastic features (Fig. 5).