Primary Extranodal Natural Killer/T-cell Lymphoma of the Bladder on 18 F-FDG PET/CT.

Extranodal NK/T cell lymphoma (ENKTCL) is an aggressive lymphoma associated with Epstein-Barr virus (EBV) infection, with bladder involvement being extremely rare and only a few cases reported. We present a case of a 75-year-old man with hematuria, where 18 F-FDG PET/CT revealed focal bladder hypermetabolism (SUVmax: 9.7) and mural thickening. Then, histopathology confirmed ENKTCL. After chemotherapy, 18 F-FDG PET/CT showed complete metabolic resolution, demonstrating the diagnostic and therapeutic monitoring value of it.