Polymyositis, pulmonary fibrosis and malignant lymphoma associated with hepatitis C virus infection.

Polymyositis has been associated with various viral infections, and a spectrum of immune-related diseases may occur with hepatitis C (HCV) infection. Both polymyositis and HCV infection may be accompanied by pulmonary fibrosis. An association between polymyositis and malignancy has also been reported. We report a 55-year-old woman accompanied cryoglobulinemia with HCV infection and manifesting polymyositis, pulmonary fibrosis and malignant lymphoma. Steroid therapy was effective to improve interstitial pneumonia, polymyositis, and liver function.