PMC6479150_01
Preoperative magnetic resonance study. Typical features of a pilocytic astrocytoma of the right dorsal part of the brainstem: A) FSE/T2, axial plane, B) FSE/T1 post-Gd, axial plane. No changes at the level of the inferior olivary nuclei: C) FSE/T2, axial plane, D) FLAIR/T2, axial plane
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The preoperative scan revealed a tumour with typical features of pilocytic astrocytoma, localised in the right dorsal part of the brainstem (Figure 1). This lesion was absent on both previous studies (Figures 1 and 2). Taking into account the patient's history, the above-mentioned imaging features raised at first the suspicion of tumour recurrence on a late postoperative scan.
Magnetic resonance study 5 days after subtotal excision of a tumour. The post-resection cavity, enlarged lateral ventricles: A) FSE/T2, axial plane, B) FSE/T1 post-Gd, axial plane. No changes at the level of the inferior olivary nuclei: C) FSE/T2, axial plane, D) FLAIR/T2, axial plane
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The early postoperative scan (five days post-surgery) showed no clear evidence of a residual enhancing tumour (Figure 2). This lesion was absent on both previous studies (Figures 1 and 2). Taking into account the patient's history, the above-mentioned imaging features raised at first the suspicion of tumour recurrence on a late postoperative scan.
Magnetic resonance study almost 13 months after surgery. Volume and signal increase at the level of the right ION - features of unilateral hypertrophic olivary degeneration (arrows): A) FSE/T2, axial plane, B) FLAIR/T2, axial plane, C) FSE/T2, coronal plane, D) 3D/Cube FLAIR, coronal plane
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T2-weighted (T2W) fast-spin echo (FSE) and fluid attenuation inversion recovery (FLAIR) images involving the right anterolateral aspect of the medulla at the level of ION (Figure 3).