Pirfenidone is a new, broad-spectrum anti-fibrotic drug, with proven in vitro and in vivo negative effects on fibroblast growth and collagen matrix synthesis. Human studies indicate promising therapeutic effects in arresting and reversing fibrosis in a variety of different conditions, where the excessive formation of fibrous tissue is a major pathogenic mechanism. Since the fibrous tissue is a significant component of neurofibroma, reduction of fibrosis could diminish tumor progression and lead to tumor shrinkage. Therefore, Pirfenidone is an excellent candidate for the treatment of plexiform neurofibromas and surgically unresectable tumors in patients with NF1.