Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder, which confers an increased risk of a wide range of cancers, and malignant tumors are the most common cause of death in individuals with NF1. Although in children with NF1, the most common neoplasms are optic nerve gliomas and brain tumors, an elevated risk of myeloid leukemia and an increased relative risk of acute lymphoblastic leukemia and non-Hodgkin lymphoma were reported. In adults with NF1, the relative risk of brain tumor is 100 times higher than in the general population. Cases of malignant lymphoma occurring in NF1 adult patients have been reported. However, the association between NF1 and lymphoproliferative diseases is still debated. We report a case of CNS primitive lymphoma in an adult patient who resulted positive for NF1 at genetic testing. At present, only one case of CNS lymphoma in an adult patient displaying clinical criteria for NF1 diagnosis has been reported.