Primary central nervous system (PCNSL) T-cell lymphoma is a very rare extra nodal non-Hodgkin's lymphoma (NHL) tumor arising from the central nervous system. The incidence of this disease is increasing globally in part due to larger numbers of immunocompromised patients. There are no pathognomonic clinical or radiographic features of T-cell PCNSL. Brain biopsy is generally necessary for tissue diagnosis in order to direct appropriate treatment and counsel patients on prognosis. We report our experience in an immunocompetent patient who presented with a several week history of progressive encephalopathy. The imaging findings, histopathological studies, treatment and review of the current literature of this rare condition are discussed.