Paraneoplastic polymyositis associated with squamous cell carcinoma of the lung.

An association between polymyositis and lung cancer has been debated. Published data usually lack either lung cancer histologic differentiation or biopsy-based delineation between polymyositis and dermatomyositis. We reported a case of a 56-year-old man with squamous cell carcinoma of the lung confined to a single hilar lymph node presenting with biopsy-proven polymyositis of 3 months in duration. Polymyositis should be considered as a potential presentation of paraneoplastic syndrome, especially in patients who are at risk for lung cancer.