What is it?

Abstract

A demyelinating pseudotumour is described in a 46-year-old man. At MRI, the lesion was displayed as a space-occupying mass in the frontal lobe which appeared inhomogeneously ipointense with the grey matter on T1-weighted images and inhomogeneously hyperintense on PD and T2-weighted images. Following gadolinium injection, the peripheral portion appeared unevenly and slightly enhanced. Histologically, the lesion was composed of mononuclear cells infiltrating the white matter and extending to the cortex. Luxol-fast blue stain revealed a diffuse loss of myelin. One year following surgery the patient is alive and well.