Fatal alveolar hemorrhage in a patient with mixed connective tissue disease presenting polymyositis features

A 22-year-old female with Raynaud's phenomenon, swollen hands and a high titer of anti-RNP antibodies developed fever and myositis. Prednisolone (40 mg/day) was considered effective for myositis since circulating myogenic enzymes rapidly decreased. However, she suddenly developed respiratory distress with bilateral pulmonary infiltrates and bloody sputum. Under the diagnosis of alveolar hemorrhage (AH), intravenous methylprednisolone pulse therapy was given, but she died of respiratory failure. Autopsy findings demonstrated massive AH with hematoma formation, and myositis in the iliopsoas muscle. Depositions of immune complex and vasculitic lesions were not recognized in her lungs.