Primary natural killer/T-cell lymphoma presenting as leptomeningeal disease

Introduction Primary central nervous system natural killer/T-cell lymphoma (primary-CNS-NK/TCL) is a rare non-Hodgkin's lymphoma. To our knowledge, only five patients have been described previously, all of whom were male, with brain parenchymal involvement and previous Epstein-Barr virus infection, it has never been reported to present as leptomeningeal disease as our case. Our objective is to report a rare case of primary-CNS-NK/TCL presenting as leptomeningeal disease and to share our diagnostic/therapeutic approach to this rare disease. Methods We report a rare case of primary-CNS-NK/TCL presenting as leptomeningeal disease. The patient was diagnosed and treated at The University of Texas MD Anderson Cancer Center. Results The patient presented with multiple cranial neuropathies and gait ataxia. Brain and spinal cord magnetic resonance imaging demonstrated leptomeningeal enhancement of the cerebellar folia/vermis, spinal cord dura, and both temporal lobes as well as adjacent brain parenchymal disease. Cerebrospinal fluid (CSF) revealed atypical lymphoma cells of NK/T-cell lineage by flow cytometric immunophenotyping. Molecular analysis using real-time quantitative polymerase chain reaction did not detect Epstein-Barr virus DNA in the lymphoma cells. Bone marrow biopsy revealed no morphologic, flow cytometric, or immunohistochemical evidence of B-, T- or NK-cell lymphoma. Slit-lamp examination demonstrated no evidence of intraocular lymphoma. Whole-body PET scan showed no evidence of malignancy other than CNS disease. The patient was given systemic chemotherapy with high-dose methotrexate, vincristine, and procarbazine, along with intrathecal therapy with free cytarabine. The patient showed clinicoradiographic improvement and CSF cytology became negative. Conclusion This case highlights an atypical presentation of primary-CNS-NK/TCL with a potentially successful treatment regimen.