Dermatomyofibroma is a recently described, benign acquired plaque-like cutaneous proliferation of fibroblast and myofibroblast. Clinically, it is located in or around the shoulder and measures from 1 to 2 cm in greatest diameter. Histologically, these are non-encapsulated but well-circumscribed, plaque-like lesions located in the reticular dermis, and composed of fascicles of monomorphic myofibroblasts, oriented parallel to the skin surface. We report a 25-year-old man with a 1.5×1.5 cm sized skin colored plaque-like mass on his left shoulder and showed the histologic finding of dermatomyofibroma. (Korean J Dermatol 2000;38(3)：380~382)