Lymphomatosis cerebri presenting as a rapidly progressive dementia: Clinical, neuroimaging and pathologic findings

Primary central nervous system lymphoma (PCNSL) usually presents with clini cal and neuroimaging findings consistent with single or multiple intracrani al mass lesions. On cranial magnetic resonance imaging (MRI), such lesions are nearly always contrast enhancing, reflecting disruption of the blood-br ain barrier at the site of tumor nodules, We describe 2 cases from the UCLA Medical Center who developed a rapidly progressive dementia due to extensi ve gray and white matter cerebral lesions involving much of the brain. In t he patient who came to autopsy, widely infiltrating, focally necrotic B-cel l plasmacytoid lymphoma was noted throughout the cerebral neuraxis, MRI fin dings in case 2 were consistent with diffuse lymphomatous brain infiltratio n without mass lesions, which was biopsy proven. We conclude that PCNSL may occur in a diffusely infiltrating form which may occur without MRI evidenc e of mass lesions or blood-brain barrier compromise, Vile refer to this ent ity as 'lymphomatosis cerebri' and add it to the differential diagnosis of a rapidly progressive dementia.