title: Sinonasal NK/T-cell lymphoma.
abstract: BACKGROUND
  Nasal NK/T-cell lymphoma is a rare but well-known clinical entity. Thanks to improvements in anatomopathology and the development of routine immunohistochemistry, the diagnosis of nasal NK/T-cell lymphoma (NK for "natural killer") was recognized by the WHO in 2001. The main differential diagnosis is with Wegener's granulomatosis. Treatment is based on radiotherapy and chemotherapy. Prognosis is poor, with variable evolution and sometimes rapid progression.
  
  
  METHODS
  The authors report the case of a 54-year-old man without known pathological history, who presented with bilateral nasal obstruction with purulent rhinorrhea. Diagnosis was made on the basis of immunohistochemical study of biopsy samples. The tumor was graded IE on the Ann Arbor classification. Treatment, comprising CHOP chemotherapy followed by radiotherapy, achieved total remission at 8 months' follow-up.
  
  
  CONCLUSIONS
  Sinonasal NK/T-cell lymphoma is rare. Diagnosis is based on immunophenotypic and molecular characteristics. It is an aggressive lymphoma, requiring multidisciplinary management. Prognosis is poor.
authors.affiliation: Service ORL et chirurgie cervico-faciale, hôpital militaire My Ismaïl, boulevard El Hanssali, Meknès, Morocco. mounirhmidi@hotmail.com
authors.forename: M
authors.initials: M
authors.lastname: Hmidi
authors.forename: M
authors.initials: M
authors.lastname: Kettani
authors.forename: A
authors.initials: A
authors.lastname: Elboukhari
authors.forename: N
authors.initials: N
authors.lastname: Touiheme
authors.forename: A
authors.initials: A
authors.lastname: Messary
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001706:Biopsy; D017024:Chemotherapy, Adjuvant / Q000379:methods; D003937:Diagnosis, Differential; D005500:Follow-Up Studies; D006801:Humans; D054391:Lymphoma, Extranodal NK-T-Cell / Q000175:diagnosis / Q000473:pathology* / Q000628:therapy*; D008297:Male; D008444:Maxillary Sinus Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000628:therapy*; D008875:Middle Aged; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D009669:Nose Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000628:therapy*; D011379:Prognosis; D018714:Radiotherapy, Adjuvant / Q000379:methods; D035583:Rare Diseases; D016896:Treatment Outcome