Dermatomyositis/Polymyositis and Lung Cancer: Report of Three Cases.

Abstract

Background: Although the association between connective tissue disease and malignant neoplasms is well known, the direct causal relationship between the two diseases is not well understood. This study attempted to evaluate the clinical behavior and whether a causal relationship between connective tissue disease and malignant tumor could be documented. Cases: We encountered three cases of lung cancer which were associated with connective tissue disease. Case 1 was a 33-year-old woman with dermatomyositis who had been treated by steroids. A right upper and middle lobectomy was performed (pT2N2M0, stageIIIa, adenocarcinoma). Case 2 was a 66-year-old woman who had received maintenance therapy by steroids from age 53 for polymyositis. Squamous cell carcinoma of the right lower lung and stomach cancer were detected. An operation was not carried out because of multiple bone metastasis. Case 3 was a 58-year-old man in whom dermatomyositis, Sjogren's syndrome and Hashimoto disease were diagnosed 6 years previously and had received treatment by steroids. A right upper lobectomy was carried out (pT4N2M0, stageIIIB, adenocarcinoma). Conclusion: We describe herein three patients who developed metastasis in the mediastinum, lung and other organs. Being rapidly progressing cancer, the growth and progress of the cancers were very rapid. The etiology and pathogenesis of the association between connective tissue disease and malignancy has not been fully elucidated. Whether the relationships between the malignant tumor and autoimmune disease is related to the immunologic abnormality, we will document our views of the evaluation for malignancy of connective tissue diseases based on the current literature and our cases.