A 77-year-old woman was admitted to our hospital because of an abnormal chest shadow. She complained of shortness of breath on effort. Chest CT showed patchy areas of ground-glass opacity in right S2 and S6. A high titer of antinuclear antibody with a discrete speckled pattern on immunofluorescent staining was disclosed, and she was positive for anticentromere antibodies. Pulmonary arterial hypertension was found by right heart catheterization. Biopsy by video-assisted thoracoscopic surgery was performed. About one month after surgery, she started to need to inhale oxygen due to gradually progressing dyspnea. Continuous PGI2 administration was not very effective, but administration of methylprednisolone and prednisolone induced improvement of her symptoms. Histopathologic examination of biopsy revealed extensive and diffuse occlusion of pulmonary veins. The pathological diagnosis suggested a pulmonary veno-occlusive disease. Clinical data suggested the association between systemic sclerosis sine scleroderma and probable pulmonary veno-occclusive disease.