Abstract
Polymyositis is an inflammatory disease that causes bilateral proximal muscle weakness; unlike dermatomyositis, it is not usually associated with malignancy. However, there are a handful of case reports documenting polymyositis in patients with lymphoma, breast, lung, and bladder cancer. Here we report a case of metastatic pancreatic adenocarcinoma disguised by presenting as polymyositis. Clinical presentation, laboratory values, muscle biopsy, and imaging were all diagnostic of paraneoplastic polymyositis. The patient has significantly improved in symptoms are receiving systemic steroids and pancreaticoduodenectomy.