A 13-year-old girl with repeated spontaneous pneumothorax and progressive dyspnea is described. The biopsy specimen of the lung showed marked proliferation of smooth muscle cells in the thickened bullous wall and alveolar septa, which was similar to the findings of the pulmonary lymphangiomyomatosis. Pulmonary lymphangiomyomatosis is one of the diseases which should be considered when children have progressive dyspnea, chylous effusions and repeated spontaneous pneumothorax.