Scleroderma is a disease of unknown cause that produces fibrosis (hardening or scarring) of the connective tissue in the skin, blood vessels, and internal organs. This results in a tight, shiny appearance of the skin and potentially life-threatening abnormalities of the lungs, heart, kidneys, and digestive tract. Scleroderma lung disease is difficult to treat. Lung inflammation (alveolitis) occurs before lung scarring (fibrosis). Cyclophosphamide is a drug that decreases inflammation; therefore, it may be useful in treating patients with scleroderma lung disease.