[An adult case of mixed connective tissue disease associated with myocardial infarction].

A 36-year-old Japanese woman with mixed connective tissue disease (MCTD) was treated with systemic Vitamin E and developed sudden myocardial infarction. The diagnosis of MCTD was based on clinical and serological findings. Since she developed pericarditis with high fever on the occasion of the attack of myocardial infarction, she was treated with systemic corticosteroid and recovered well. Although MCTD had been recognized as a disease with good response to corticosteroid and good prognosis, some cases suffer from interstitial pneumonia, pulmonary hypertension and myocardial infarction with poor prognosis.