Primary central nervous system lymphoma in a patient with multiple sclerosis using fingolimod.

Primary central nervous system lymphoma (PCNSL) is an uncommon lymphoproliferative disease associated with immunosuppression. Here, we report the case of a patient with multiple sclerosis, under treatment with fingolimod (FTY720, Gilenya) for 4 years, who developed this condition. Although the causal relationship cannot be established, there are cases in the literature that describe the appearance of lymphoma after the use of this medication. Considering the high mortality of PCNSL, epidemiological studies are necessary to establish a relationship between its arising and the use of immunosuppressants.