A Case of Nasal NK T-Cell Lymphoma Presenting With Persistent Epiphora.

Nasal type natural killer/T-cell lymphoma (NNKTL) is a rare and aggressive subtype of non-Hodgkin lymphoma originating from a natural killer cell or γδ T cell infected by the Epstein-Barr virus. It usually invades the aerodigestive tract and can rapidly destroy the paranasal sinus, hard palate, and central nervous system. NNKTL is often mistaken for benign conditions such as chronic hypertrophic rhinosinusitis or mucosal inflammatory change, as endoscopic findings of NNKTL presenting nasal mucosal hypertrophy are similar to endoscopic findings for these abovementioned benign conditions. Here, the authors report the diagnosis and examination of NNKTL in a 58-year-old male patient who visited our clinic for nasal cavity discomfort after he underwent a dacryocystorhinostomy to treat dacryocystitis.