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

Background: 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.

Conclusions: This case highlights an atypical presentation of primary-CNS-NK/TCL with a potentially successful treatment regimen.