Rheumatic diseases can be a paraneoplastic syndrome for an occult neoplasia. Some syndromes are more characteristic than others. In this case report, we present a patient with musculoskeletal symptoms suggestive of both carcinomatous arthritis and polymyalgia rheumatica that was shown to have adenocarcinoma of the lung. The musculoskeletal symptoms accompanied the course of the disease, disappearing with the treatment and re-occurring when it relapsed.