Lymphomatosis Cerebri Presenting as Rapidly Progressive Dementia

BACKGROUND: As the population ages, the incidence of dementing illness is increasing. Accurate and timely diagnosis provides the best hope for instituting appropriate treatment and educating the patient and family members as to prognosis based upon likely etiology in a given patient. REVIEW SUMMARY: We present a case of an elderly patient referred to our tertiary-care center for further evaluation of a rapidly progressive dementia, whose definitive diagnosis was delayed by nonspecific MRI findings, presence of 14-3-3 protein in the CSF, and nonspecific cutaneous lesions. At brain biopsy, he was thought to have a diffusely infiltrating lymphoma, with distinctive immunohistochemical features. CONCLUSION: This case is notable in that it presents a patient with progressive dementia whose diagnosis of primary central nervous system lymphoma (PCNSL) was delayed because of the lymphoma's atypical diffusely infiltrating nature. Awareness of this unique presentation may hasten the time between clinical presentation, diagnosis, and subsequent treatment.