Primary central nervous system vasculitis mimicking a brain tumor on conventional magnetic resonance imaging: the usefulness of perfusion-weighted imaging. A case report

Excerpt

A 31-year-old woman presented with headache and subacute aphasia. Brain magnetic resonance imaging (MRI) (Fig. 1) showed a left temporal lobe intraaxial mass of 2.6 × 1.8 × 2.5 cm. The lesion was first identified on T2-weighted images where the peripheral, solid part of the mass was isointense to gray matter and the central part hyperintense, consistent with necrosis. Gadolinium-enhanced T1-weighted images showed a peripheral “ring-enhancement”. MR angiography was normal. Diffusion-weighted MRI with apparent diffusion coefficient map (DWI–ADC) showed low diffusion value (0.000870 mm²/s) in the solid portion of the mass, and high diffusion value (0.00194 mm²/s) in the central portion, confirming central necrosis. Dynamic susceptibility contrast perfusion-weighted MRI (DSC-PWI) demonstrated low relative cerebral blood volume (rCBV) in both lesion wall (mean value 0.76) and perilesional area, compared to normal white matter. Biopsy revealed ischemic necrosis without cellular atypia, coupled with perivascular and transmural infiltrate of lymphonuclear cells involving the vessels, which caused narrowing of their vascular lumen. History did not reveal any underlying disease, including immune disorders. Antinuclear antibodies, antineutrophil cytoplasmatic antibodies, and rheumatoid factor were normal. A diagnosis of primary central nervous system vasculitis (PCNSV) was then established. Steroid therapy was immediately initiated. Two months later, clinical examination was negative and brain MRI showed gliotic–malacic evolution without new intracranial lesions.

…