DEMYELINATING DISEASE VERSUS TUMOR IN SURGICAL NEUROPATHOLOGY - CLUESTO A CORRECT PATHOLOGICAL DIAGNOSIS

Clinical presentations as well as radiological and histopathological f indings in biopsies from patients with multiple sclerosis (MS) or othe r demyelinating disorders of the central nervous system are sometimes misleading, resulting in an erroneous diagnosis of brain or spinal cor d tumor. We report 17 patients who presented with symptoms mimicking t hose of brain (14 cases) or spinal cord (three cases) tumors. Computer ized tomography or magnetic resonance imaging studies or both were int erpreted as consistent with a tumor in each case. All patients underwe nt surgery, and all 17 pathological specimens were eventually diagnose d as showing demyelinating disease, usually consistent with MS. In eac h case we examined a variety of histological features and immunohistoc hemical studies and addressed their relative importance in considering the diagnosis of MS. All cases showed perivascular lymphocytic inflam mation with variable amounts of macrophage infiltration, necrosis, and edema. The hypercellularity of the lesions and the presence of atypic al reactive astrocytes with mitotic figures were the disturbing featur es that might have led to the erroneous diagnosis of an astrocytic neo plasm. Immunohistochemistry for astrocytic (glial fibrillary acidic pr otein) and macrophage (HAM-56) markers are helpful in evaluating biops ies. Our results emphasize the need to perform special stains (i.e., f or myelin and axons) that demonstrate myelin loss and relative preserv ation of axons and allow a correct diagnosis.