A rare case of primary anaplastic large cell lymphoma of the central nervous system

Primary central nervous system lymphoma (PCNSL) is an uncommon variant of extranodal non-Hodgkin's lymphoma, confined to the central nervous system (CNS) and is usually seen in immunocompromised patients. The vast majority of cases are of the B-cell type and T-cell PCNSL is rare. Here, we report an 18-year-old male who presented with fever, headache, and history of seizures. On evaluation, he was found to have a left parieto-occipital mass which was completely excised. Histopathology was suggestive of a T-cell neoplasm and immunohistochemistry showed tumor cells positive for leukocyte common antigen, anaplastic lymphoma kinase (ALK), CD30, and CD4 which confirmed the diagnosis of ALK-positive anaplastic large cell PCNSL. There was no evidence of disease outside the CNS. He was started on the DeAngelis protocol for PCNSL. To the best of our knowledge, only 27 cases of anaplastic large cell PCNSL have been previously reported in literature.