This report describes a patient who presented with an unusual polyarthritis syndrome. After extensive evaluation, squamous cell carcinoma of the lung was diagnosed. During the course of the illness, the patient developed vasculitic features and "rheumatoid-like" nodules. Two months after the administration of combined-modality therapy for stage IIIA non-small cell lung carcinoma, the signs and symptoms of polyarthritis and vasculitis had disappeared completely. Ten months later, the patient remains in clinical remission. This is the first published report of simultaneous vasculitic and polyarticular manifestations in a patient with carcinoma polyarthritis.