"Gliomatosis cerebri" simulating an acute diffuse encephalomyelitis. Case report.

Neuroradiologic, neuropathologic and immunohistochemical features are reported in a young man with a impairment of the central nervous system mimicking an acute diffuse encephalomyelitis. A white male, 17 years old, healthy till 4 months before, when developed a right hemiparesis and after 2 months a bilateral hemiparesis with a progressive impairment of several cranial nerves. Magnetic resonance imaging showed multiple lesions without a mass effect that suggested myelin loss. He remained unconscious for almost one month before dying of pneumonia. The neuropathologic examination showed a heavy brain (1505 g) with herniations and a large right midbrain. There were several soft and pink areas mainly at the right midbrain, left cerebellum and in the white matter of the left cerebral hemisphere. The histopathologic sections showed diffuse blastomatous proliferation without total replacement or destruction of the original tissue. The tumor cells had astrocytic, oligodendrocytic and spongioblastic phenotypes, some of them with a GFAP-positive reactivity. There were focal anaplastic changes. The diagnosis of "gliomatosis cerebri" was only possible by the autopsy.