Abstract
A 79-year-old man was referred to our hospital with scaly erythema on his trunk and extremities, general fatigue, and severe muscle weakness. He had elevated levels of serum creatine kinase (13366 U/L) and aldolase (36.0 U/L). Computed tomography showed lung cancer that seemed to have spread to the pleura, mediastinal lymph nodes, and liver. Histopathological examination of a needle biopsy specimen of the lung cancer confirmed squamous cell carcinoma. Muscle biopsy results were negative. However, Magnetic resonance imaging of his thigh muscles suggested myositis. Based on these findings, the patient was diagnosed with malignancy -associated dermatomyositis (DM). He was treated with oral prednisolone at 60 mg per day; cutaneous manifestations improved, but muscle weakness persisted and dysphagia appeared. The lung cancer was treated with chemotherapy; however, the patient died 2 months after his first visit. This patient showed positivity for anti-TIF1 antibody, which has been reported to be a marker of malignancy -associated DM. Many malignant tumors associated with DM develop after diagnosis of DM. Therefore, testing for anti-TIF1 antibody is beneficial in predicting the risk of malignant tumors in patients with DM.
