Dermatomyositis as a symptom of primary lung cancer: A case report and review of the literature.

Dermatomyositis (DM) is a rare autoimmune disease associated with manifestations of proximal muscle weakness and typical cutaneous skin rash. Patients with DM have a higher incidence rate of cancer, compared with the general population, since DM usually presents as a paraneoplastic syndrome. The present study reports a case of a 69-year-old male patient presenting with typical cutaneous rash and aggravating proximal muscle weakness for 3 months. When first admitted to the Department of Dermatology of Shandong Provincial Hospital Affiliated to Shandong University (Jinan, China), the patient was diagnosed with DM. Subsequently, chest computed tomography scan revealed a neoplasm located in the right upper lobe. Video-assisted thoracoscopic surgery right upper lobectomy and lymph node dissection were then performed. The patient experienced a fast recovery from the surgery. The removal of the neoplasm clearly improved the symptoms of DM. Considering that DM is usually associated with the existence of a tumor, cases of DM require a thorough diagnostic investigation in order to exclude an underlying malignancy.