Extranodal NK/T cell lymphoma, nasal type, with retrobulbar extraconal phlegmon and naso-oral fistula.

Extranodal natural killer (NK-)/T cell lymphoma, nasal type (ENKL), 1 is a rare disease that often mimics rheumatological and infectious conditions and can therefore be difficult to diagnose. The authors present a case of a 55-year-old Vietnamese woman who was misdiagnosed with severe atrophic rhinitis and chronic sinus osteitis. Over a period of 8 months from initial referral, she underwent multiple biopsies and was treated with various antimicrobial regimens until the histopathological diagnosis of ENKL was finally made. Her presentation was complicated by bacterial dacrocystitis, preseptal cellulitis and a retrobulbar extraconal phlegmon requiring surgical drainage. She also subsequently developed a naso-oral fistula on treatment. This case highlights the importance of repeated biopsies, in particular from non-necrotic regions of the sinonasal tract when a patient does not respond to therapy and clinical suspicion of neoplastic pathology remains. This is the first case of ENKL to describe significant orbital complication.