Extranodal natural killer (NK)/T-cell lymphoma is a very rare and aggressive disease characterized histopathologically by an Epstein-Barr virus (EBV)-positive atypical lymphoid cytotoxic infiltrate, extensive vascular destruction, and prominent tissue necrosis. It commonly shows cutaneous lesions that primarily or secondarily mimic cellulitis at the primary site. We report on a very rare case of extranodal NK/T-cell lymphoma, nasal type of skin/soft tissue, in a 64-year-old man, and describe the radiological findings. The condition was misdiagnosed as cellulitis of the left arm based on initial noninvasive clinical and radiologic work-up.