Nasal-Type Extranodal Natural Killer/T-Cell Lymphoma Mimicking Recurrent Sinusitis: A Case Report and Review of the Literature

: Nasal-type extranodal natural killer (NK)/T-cell lymphoma (ENKTL) is a rare type of lymphoma that is endemic to East Asia. It typically demonstrates as a destructive mass involving the midline facial tissues that causes rhinosinusitis symptoms such as nasal obstruction, sinusitis, ulcer, and epistaxis. The diagnostic tendency of nasal-type ENKTL is to use computed tomography (CT), but this may present infiltrative patterns without a prominent mass, making it difficult to distinguish ENKTL from benign inflammatory diseases. Here, we report a 59-year-old male with a chief complaint of rhinosinusitis symptoms, mimicking chronic sinusitis and a CT scan showing a typical right sinusitis pattern. Functional endoscopic sinus surgery was performed and a positive culture was consistent with the diagnosis. However, histopathological and immunohistochemical evaluation established the diagnosis of nasal type ENKTL. Follow-up positron emission tomography-computed tomography (PET-CT) also corresponded with this diagnosis, and therefore, radiotherapy and chemotherapy were indicated.