The results of the autopsy of a 38-year-old female with mixed connective tissue disease who had suffered from painful subcutaneous calcification in her buttocks and extremities for 14 years and died from rapidly progressive pulmonary hypertension are reported. On autopsy, her heart and lungs revealed changes of severe pulmonary hypertension with intimal thickening and plexiform lesions in the small pulmonary arteries which had resulted in the collapse of both lungs and caused marked dilatation and hypertrophy of the right ventricle of the heart. Microscopic examinations of the subcutaneous calcified tissues indicated that the calcification may have been caused by repeated panniculitis.