Specific Imaging Findings

On non-enhanced CT scans, meningioangiomatosis (MA) may appear as a nodular calcification, as a thickened gyriform mass with or without surrounding hypodense edema, or as hypodense lesion with central calcification. On MRI it is of either low T1 signal, or shows a mixed signal on both T1- and T2-weighted images, depending primarily on the amount of calcific deposition. A pattern of gyriform hyperintensity has been recently reported as a characteristic feature on FLAIR. Contrast enhancement is usually very prominent and may show a gyriform distribution. Surrounding vasogenic edema involving the adjacent white matter is quite common, and the lesion may cause mass effect. Advanced imaging techniques such as MRS may be degraded by contamination artifacts due to calcific deposition; nevertheless, increase in the choline peak with loss of the n-acetyl aspartate peak have been described. Imaging findings are often nonspecific and do not allow for a definite diagnosis.

Pertinent Clinical Information

MA usually affects children and young adults, with a male predominance; it may occur sporadically (most of reported cases) or in association with NF2 (approximately 20%), when it is often multifocal. Sporadic and NF2-associated forms are histologically similar but clinically different. The sporadic type typically presents with partial seizures that are difficult to control, whereas lesions associated with NF2 are often asymptomatic and discovered incidentally. The genetic basis of the sporadic form is not well clarified.