[Cutaneous necrosis is predictive of cancer in adult dermatomyositis]

Adult dermatomyositis is associated with cancer in 15 p. 100 to 50 p. 100 of cases and, hence, investigations should be systematically performed to search for cancer. A number of predictive factors have been reported. The aim of our study was to search for predictive factors of cancer, among adults with dermatomyositis.

We prospectively assessed 26 adults presenting with dermatomyositis, hospitalised in our department of dermatology from January 1993 to June 2000. The parameters assessed were: association with a cancer, age, gender, cutaneous necrosis, muscular weakness, electromyographic abnormalities, erythrocyte sedimentation rate, and muscular enzyme levels.

Mean age was of 52 years and sex ratio (M/F) was of 0.53. Cancers were diagnosed in eight cases (31 p. 100) (mean age: 59.5 years; sex ratio=1; cancer localization: lung (2), breast (2), ovary, endometrium, bladder, and melanoma). Five patients in the cancer group had cutaneous necrosis and only 2 in the without cancer (p=0.01; PPV=71.4 p.100). Elevation of muscular enzyme was also associated with cancer.

Our report demonstrates that cutaneous necrosis is closely associated with cancer and it suggests that in selected patients with dermatomyositis and cutaneous necrosis, more exhaustive and repeated investigations should be performed to search for cancer. The interest of elevation in muscular enzyme as a predictive factor of cancer is discussed.