Inclusion body myositis

ABSTRACT

Inclusion body myositis was diagnosed based on three muscle biopsies on a 24-year-old woman during a 10-month period. She presented with a four-year history of severe painless weakness in her leg muscles that was refractory to both corticosteroid and cytotoxic drugs. Immunostaining for mumps viral antigen was positive for nuclear and cytoplasmic inclusions in skeletal muscle cells.