A case of small cell lung cancer presenting with air space consolidation during the course of treatment of interstitial pneumonia associated with systemic sclerosis

Abstract

Background. Although invasive mucinous adenocarcinoma is known as a primary lung cancer, presenting with radiologic findings like pneumonia, it is rare for small cell lung cancer to present with similar findings. It is also rare for systemic sclerosis to be associated with small cell lung cancer in Japan. We herein report a case of small cell lung cancer presenting with air space consolidation during the course of treatment of systemic sclerosis. Case. A 74-year-old man was referred to our hospital with a complaint of dyspnea on exertion. He was diagnosed with systemic sclerosis based on findings of interstitial pneumonia, skin thickening and anti-RNA polym-erase III antibody positivity. While the interstitial pulmonary changes on chest radiographs were slightly improved by treatment with prednisolone and cyclophosphamide, non-segmental consolidation in the subpleural area of the right upper lobe appeared after two weeks of treatment. Although it was assumed to be invasive mu-cinous adenocarcinoma, a trans-bronchial lung biopsy revealed it to be small cell carcinoma. He was treated with chemotherapy. Conclusion. Patients with systemic sclerosis rarely but occasionally develop small cell lung cancer presenting with air space consolidation. We should be alert for concomitant malignancy when anti-RNA polym-erase III antibody is associated with systemic sclerosis.