A rare, malignant neoplasm mainly affecting men in the fifth decade of life, that usually arises in the nose, paranasal sinuses, orbits or upper airway, and that can present with a nasal mass, nasal bleeding, nasal obstruction, palate perforation (i.e. midline perforation of the hard palate), and mid-facial and/or upper airway destructive lesions. In advanced disease stages, which are associated with a poor prognosis, NKTCL may disseminate to other organs. A few cases of NKTCL presenting primarily in the lymph nodes have also been described. The disease is Monarch Disease Ontology entry MONDO_0019472 (extranodal nasal NK/T cell lymphoma). Also known as: Extranodal NK/T lymphoma-nasal, Extranodal NK/T-cell lymphoma, nasal type, NK/T-cell lymphoma, NKTCL, angiocentric T-cell lymphoma, lethal midline granuloma, nasal T/natural killer-cell lymphoma, nasal type Extranodal NK/T-cell lymphoma.