We describe an occurrence of small cell carcinoma of the lung in a 37-year-old woman with rheumatoid arthritis who did not receive any kind of cytotoxic agents for the rheumatic condition. There seemed to have no predisposing factor for the development of malignancy. The diagnosis of small cell carcinoma was based on repeated hemoptysis and cytologic finding of a rapidly growing mass over the forehead. The patient responded dramatically to chemotherapy with rapid resolution of forehead mass, relief of arthritis in the hands, and decrease of serum rheumatoid factor from 4800U/ml to 1200U/ml. This appeared to be the first report of small cell carcinoma of the lung developing in a patient with rheumatoid arthritis.

Small cell carcinoma of the lung can develop in patients with rheumatoid arthritis, and chemotherapy effectively resolves the forehead mass and reduces rheumatoid factor levels.

Small cell carcinoma of the lung in a patient with rheumatoid arthritis: a case report.

Key Takeaway: Small cell carcinoma of the lung can develop in patients with rheumatoid arthritis, and chemotherapy effectively resolves the forehead mass and reduces rheumatoid factor levels.