Introduction: Primary central nervous system lymphoma accounts for 1%-3% of all central nervous system (CNS)(1). Natural Killer/T cell lymphomas (NK/TCL) generally occurs in the adult male (2) and are commonly extranodal and usually present at midline facial structures, where they can reach the central nervous system. (3) Previously reported treatments include radiation, intrathecal chemotherapy and systemic chemotherapy. The overall success of treatment is poor with a median overall survival of 5 months (1)

Methods: We describe the clinical course and treatment of a patient with a NK/T cell lymphoma and a literature review of this lymphoma presentation.

Results: A 79-year-old female who started with a decreased visual acuity in the right eye, then progresses with confusion and decreased strength in the left side of the body. The examination showed hemiparesia, hypoesthesia and hyperreflexia on the upper and lower left limbs and a markedly confusion syndrome. The Magnetic Resonance Image showed a right occipital lesion with 37cm3 of volume, with areas of hemorrhage; the spectroscopy presented a peak N-acetylaspartate with a retaining choline peak. The patient was taken to surgery, the histopathological report demonstrated a NK lymphoma cells with CD56-positive. Radiotherapy with 35 Gy was administered; chemotherapy could not be administered because the patient presented a quickly deterioration of her basal state, she died 108 after diagnostic.

Conclusions: Clinical information regarding the NK/TCL is not abundant. It is important that within the spectrum of intracranial lesions, lymphomas are considered as a differential diagnosis. A midline presentation and insidious clinical course, like our case, we must search of NK/TCL, so we can start the management and probably we could give a better chance to survive to the patient.

Patient Care: The knowledge of different pathology could be the answer for some cases that the usual manifestations do not fit, so we can give more options for treatment and it could improve the quality of life of our patients

Learning Objectives: 1. To know the clinical characteristics of patients with primary central nervous system Natural killer/T-cell lymphoma 2. Identify the key points in neuroimaging to suspect this type of injury. 3. Achieve de adecuate differentiation of NK cells vs B lymphomas by inmunohistochemestry.

References: 1. Li L. Beng-teck B. Kan-suen J. et al. Primary Central Nervous System Natural Killer Cel Lymphoma in a Chinese Woman with Atypical 11C-Choline Positron Emision Tomography and Magnetic Resonance Spectrometry Findings. World Neurosurg. 2015;84: 4:1176.e5-1176.e9 2. Bian S. Wai K. Murugaya S. et al. Nasal-type extranodal natural killer/T-cell lymphomas: a clinicopathologic and genotypic study of 42 cases in Singapore. Modern Pathology. 2004;17:1097-1107 3. Kaluza V. Rao D. Said J. et al. Primary extranodal nasal-type natural killer/T-cell. Human pathology. 2006;37:769-772