Autopsy case of primary central nervous system lymphoma with subacute mental deterioration and progressive white matter lesions in an elderly man

An autopsy case is reported here of a 70-year-old Japanese man with primary central nervous system lymphoma (PCNSL) manifesting subacute mental deterioration and progressive white matter lesions. Brain magnetic resonance imaging (MRI) revealed irregular hyperintense lesions on T2-weighted images of the white matter of the bilateral frontal lobes. The hyperintense lesions then spread to the corpus callosum, internal capsule, globus pallidus and along the pyramidal tract in the brainstem without a mass effect. The U-fibers were also involved in some regions. Neither brain swelling nor a significant atrophy was observed. The clinical manifestations and imaging findings of PCNSL are diverse. Recently, some reports have revealed atypical MR imaging of PCNSL exhibiting diffuse infiltration in the brain parenchyma without mass formation and enhancement of the lesions after the administration of a contrast medium. The authors also encountered an interesting case of PCNSL presenting as progressive white matter lesions without brain swelling. It is now possible to finely observe white matter lesions by brain MRI, particularly in T2-weighted images. Recently the number of immunocompetent elderly patients with PCNSL appears to be increasing in Japan. Autopsy of the present case revealed an intermediate lymphocytic malignant lymphoma. Because imaging and laboratory findings are not completely specific for the diagnosis of PCNSL at present, brain biopsy is more strongly recommended for the final diagnosis of PCNSL even in elderly patients, based on which appropriate treatment is administered.