[Peripheral T-cell lymphoma, not otherwise specified accompanied by central nervous system involvement with features of lymphomatosis cerebri].

Lymphomatosis cerebri (LC) is a rare variant of primary central nervous system lymphoma, and it is characterized by diffuse cerebral infiltration of malignant lymphoma cells without evidence of a mass lesion. Herein, we report a patient with systemic peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) who had central nervous system involvement mimicking LC. A 72-year-old immunocompetent male presented with rapidly progressive dementia. Fluor-deoxy-glucose (FDG) -positron emission tomography revealed increased FDG uptake in the bone and skin. Histopathological examination of the skin lesion revealed PTCL-NOS infiltration. A FLAIR MRI scan of the brain revealed diffuse hyperintense lesions in the cerebral white matter of both hemispheres. These lesions were not enhanced with gadolinium, and there was no perceptible mass effect. We performed a brain biopsy, and the histology results were consistent with PTCL-NOS. The patient was treated with corticosteroid and chemotherapy; however the disease progressed, and he died 4 months after the diagnosis. This was a rare case of systemic lymphoma accompanied with central nervous system involvement mimicking LC.