Pulmonary lymphangioleiomyomatosis is a rare disease, prevalent in women of reproductive age, and characterized by proliferation of atypical smooth muscle in the lung. A 44-year-old women with pulmonary lymphangioleiomyomatosis was presented. Chest radiographs showed diffuse increased reticulonoular infiltrations on the almost entire lung and high resolution CT illustrated multiple, well defined cystic lesions which were distributed diffusely through the lung. Histologic confirmation of lymphangioleiomyomatosis was made upon open lung biopsy. Treatment with methylprogesterone was initated.