Prognosis factors and predictive signs of malignancy in dermatomyositis.

Introduction: Prognosis in dermatomyositis is severe, partly due to the development of cancer. The aim of this study was to identify factors predicting cancer development and assess factors predicting reduced survival rate. Patients and methods: A retrospective analysis of 32 cases of dermatmyositis diagnosed on the basis of the Bohan and Peter criteria was performed. Diagnosis was certain in 7 cases, probable in 13 and possible in 5. Then were thus 7 cases of pure cutaneous dermatomyositis. Clinical and laboratory data were compared between patients with and without cancer and between deceased and surviving patients. Results: Overall mortality was 37.5% at 4 years, confirming the gravity of dermatomyositis. Malignancy developed in 9 patients (28.1%) leading to death in all cases, within 18 months in 8. Amyopathic dermatomyositis was observed in 2 of these patients. Necrotic skin ulcerations (p < 0.01) and pruritis (p < 0.05) were significant predictive factors for the development of cancer. Poor prognosis factors were malignancy (p < 0.001), necrotic skin ulcerations (p < 0.01), and pruritis (p < 0.05). Conclusion: Prognosis is poor in certain sub-groups of patients with dermatomyositis. Such patients can be identified on the basis of skin lesions, notable necrotic ulcerations.