Dermatomyositis and Malignancy

Although there appears to be an increased incidence of malignancy among patients with dermatomyositis, demonstration of definitive statistical significance is precluded by the lack of large, controlled series. Patients with the two diseases tend to be older than the general dermatomyositis population and younger than those with cancer alone; and there is a preponderance of female patients. Tumors of the ovary and stomach are more frequently observed than in the general population, while colorectal malignancies are underrepresented. Most reported cases show development of the diseases within a year of one another, and, in some patients, the course of the myopathy follows that of the tumor. No definitive cause for the myopathy in these patients has been established.