A rare case of severe myositis as paraneoplastic syndrome on breast cancer.

Background: Dermatomyositis and polymyositis are both types of idiopathic inflammatory myositis characterized by inflammation and weakness of proximal skeletal muscles and skin rash.

Case: A 49-year-old Caucasian woman recently diagnosed with breast cancer classified as T1N2M0, stage IIIA, presenting skin rash associated with heliotrope and Gottron's papules. In addition, there was a progression to a severe reduction in proximal muscle strength with severe dysphagia.