A Patient with HCV Infection and a Sustained Virological Response to Direct-acting Antiviral Treatment Who Developed Inclusion Body Myositis.

We report the case of a 75-year-old woman who was found to have hepatitis C virus (HCV) infection in 1987. Before treatment in 2016, she was found to have mixed cryoglobulinemia (MC). Direct-acting antiviral (DAA) treatment produced a sustained virological response 12 (SVR12). She noticed gradual muscle weakness in 2015 and the gradual development of dysarthria and dysphagia in 2017. We performed a muscle biopsy that showed inclusion body myositis (IBM). To the best of our knowledge, this is first case of a patient with HCV infection, MC, and IBM, in which MC and IBM did not improve after an SVR12 was obtained by DAA treatment.