We report an unusual finding of tumor involving the ulnar nerve in the hand. An 18-year-old female patient presented with a soft swelling in her right hand for 10 years. Neurological examination was normal. However, she had discomfort or pain when using her right hand frequently. Surgical exploration revealed that ulnar nerve and its digital branches were infiltrated by fibrolipomatous tissues. The infiltrating tumor underwent surgical debunking as it was encircling the ulnar nerve. Histological examination yielded the diagnosis of a neural fibrolipoma of the ulnar nerve. The result of surgical debulking was satisfactory. Postoperatively, there was no neurologic deficit and the patient had normal sensation and motor function.