Parasagittal meningioma en plaque with extracranial extension presenting diffuse massive hyperostosis of the skull

Abstract

Background We describe a case of convexity meningioma en plaque (MEP) invading the skull and scalp with diffuse massive hyperostosis, presenting striking radiological findings. Case description A 48-year-old woman was admitted to our hospital with headache, general fatigue, diplopia, and blurred vision. A skull X-ray film, computed tomography (CT), and 3-dimensional CT demonstrated diffuse significant hyperostosis and sclerosis in the cranial vault. Magnetic resonance (MR) imaging revealed a frontoparietal, well-enhanced extra-axial mass lesion, which is compatible with findings of MEP. The tumor was partially resected. Histological examination revealed massive tumor invasion into the dura mater, hyperostotic skull, and scalp. Conclusion Hyperostosis is frequently observed in MEP, although there has been no report of a case of MEP such as ours demonstrating diffuse tumor extension and diffuse hyperostosis. Analyzing the CT finding of hyperostotic bone is useful for differentiation of MEP from other diseases that include a hyperostotic condition.