Teaching NeuroImage: Syringomyelia Secondary to Posterior Fossa en Plaque Meningioma

A 36-year-old woman presented with a 2-year history of unsteady walking. Examination showed hoarse voice and weakness of the left shoulder. CT revealed thickening of the left occipital and temporal bones (Figure 1), which was thought to be fibrous dysplasia. Brain MRI demonstrated a giant posterior fossa lesion and cervical syringomyelia (Figure 2). The lesion was noted to involve dura mater. Subtotal resection was performed. Pathology confirmed the diagnosis of en plaque meningioma (WHO grade I). Cell proliferation index Ki-67 was 2%. En plaque meningioma is a rare subtype of meningioma characterized by “sheet-like” patterns of growth.1 Significant hyperostosis is often observed.