Proliferative fasciitis is a subcutaneous or fascial reactive process that contains fibroblasts and myofibroblasts. It is identical to proliferative myositis except that it arises in an extramuscular location. This disease affects primarily middle-aged and older individuals and is rare in children. This is in contrast to nodular fasciitis, which is most common adolescents, young adults and children. It primarily affects the forearm and thigh, and most of these lesions are less than 3 centimeters in diameter. This lesion often has a rapid clinical evolution and develops within 1-3 weeks. It involves the fascia and subcutaneous tissue. This type of lesion is benign and does not recur following surgical excision.