Primary central nervous system extranodal NK/T-cell lymphoma, nasal type: case report and review of the literature.

Primary central nervous system (CNS) extranodal NK/T-cell lymphoma, nasal type (NKTCL), is an extremely rare tumor. To the best of our knowledge, only four cases have been described previously. Here, we report a case of primary CNS NKTCL in a 25-year-old immunocompetent Chinese male. The patient presented with worsening dizziness, headaches, and vomiting for approximately 2 weeks. Magnetic resonance imaging demonstrated three masses with solid components entirely in the parenchyma of the right hemisphere, and no sinonasal/nasopharyngeal lesions were found. The patient underwent a partial resection of the right temporal mass. Histological examination revealed that intermediate-sized, pleomorphic lymphocytes were arranged in an angiocentric distribution with large geographic necroses. The tumor cells expressed CD3ε, CD56, TIA-1, granzyme B, and Epstein-Barr virus-encoded RNAs. A rearrangement study showed T-cell receptor γ-chain gene rearrangement with monoclonal appearance. Postoperative chemotherapy and radiotherapy were also given, but the lymphoma failed to respond to therapy and the patient died 18 months later. Our observation and the four others found in the literature indicate that primary CNS NKTCL occurs predominantly in adult males. This is the youngest patient with primary CNS NKTCL reported.