Progressive overlap syndrome due to small cell lung cancer as a paraneoplastic syndrome.

The association between rheumatic diseases and malignancy has been documented in many studies. Polymyositis and especially dermatomyositis are associated with a higher risk of malignant disease. Furthermore, lung cancer usually develops in patients with a prolonged history of systemic sclerosis accompanied by pulmonary fibrosis. Though overlap syndrome is rarely reported in the associated cancer, this is the first report describing progressive overlap syndrome in small cell lung cancer as a paraneoplastic syndrome.