Inflammatory demyelinating disease mimicking malignant glioma.

UNLABELLED The differential diagnosis between inflammatory demyelinating disease and malignant glioma is difficult based only on neuroimaging methods. METHODS Four patients with inflammatory demyelinating disease who presented with clinical and neuroimaging findings strongly suggestive of malignant glioma were examined. RESULTS MRI showed a mass lesion with prolonged T1 and T2 values and gadolinium enhancement in all cases. Proton MR spectroscopy and (201)Tl SPECT showed findings supportive of the diagnosis of malignant glioma in all cases. However, surgical biopsy revealed inflammatory demyelinating disease. After the diagnosis, 2 patients were treated by steroid administration and 2 were just observed. The gadolinium enhancement of all lesions decreased and finally disappeared. CONCLUSION Such cases illustrate the importance of considering a demyelinating lesion in the differential diagnosis of a mass lesion. The difficulties encountered in establishing the correct diagnosis of inflammatory disease are related to the variations in the radiologic appearance, which require exclusion of gliomas or other brain tumors by surgical biopsy before the therapeutic strategy can be selected.