Pseudotumoral demyelination: a diagnosis pitfall (report of three cases)

Rare forms of demyelinating disease such as Balo's concentric sclerosis or Schilder's disease may simulate brain tumors, both clinically and on the co mputed tomography (CT) and magnetic resonance imaging (MRI). Even the histo pathological diagnosis after a biopsy is not entirely reliable. We report t hree cases of pseudotumoral demyelinating disorders having required a stere otaxic biopsy, one of which was erroneously diagnosed as a malignant astroc ytoma. We describe MRI especially the intense contrast enhancement with ill -defined margins, and the mild mass effect. We then detail the histopatholo gical processes upon which differential diagnosis with a tumor can be based .