Subcutaneous Extension of Parasagittal Atypical Meningioma Through Parietal Foramen.

Meningiomas extended to the scalp without any bony changes are rare. A 79-year-old man presented with a large subcutaneous mass in the midline parieto-occipital region and progressive right hemiparesis. The contrast-enhanced millimetric computed tomography scans of the head showed the intracranial parasagittal enhanced mass invading the superior sagittal sinus and the subcutaneous mass without any bony destructive, osteoblastic, or osteolytic changes. Under the operative microscope, no visible communication was found between the intracranial and extracranial mass lesions. Histopathologic examination of both intracranial and extracranial tumors demonstrated the same atypical meningioma (World Health Organization grade II). The possible route of extracranial extension of the tumor may be the sizable parietal foramen.