Glioblastoma with markedly reduced contrast enhancement after corticosteroid administration: Increased density and reduced diffusion capability are noteworthy.

Corticosteroids are widely used to manage peritumoral edema and associated neurological deficits in patients with brain tumors. We describe the case of a 71-year-old male patient with glioblastoma in which contrast enhancement decreased on radiographic imaging following corticosteroid administration, which has been reported previously in only 9 cases. This report aims to discuss radiographic changes in glioblastoma (density on computed tomography and diffusion capability on diffusion-weighted magnetic resonance imaging, in addition to enhancement on contrast-enhanced T1-weighted magnetic resonance imaging) following steroid administration and also following steroid discontinuation.