Dermatomyositis: A review of the cases seen in our hospital during 13 years

Abstract

Objective: Dermatomyositis (DM) is an idiopathic inflammatory myopathy with clear diagnostic criteria. In patients older than 50 years, DM has a significant association with malignancy, with an incidence of cancer in 20–40% in the most important series. We review the clinical features of the cases of DM diagnosed between 2000 and 2013 in our hospital, in order to compare them with previous series of literature. Methods: We review the medical records of all patients discharged from our hospital in the last 13 years with a diagnosis of DM, and we study epidemiological data, clinical features, association with other diseases, diagnostic tests, treatment received, and survival. Results: We recovered 13 cases of DM, 6 men and 7 women, aged 12 to 83 years (mean 61). Time from onset of symptoms to diagnosis of DM varied between 20 days and 8 months. We found 1 juvenile DM, 1 amyopathic DM, 2 DM associated with connective disease (1 rheumatoid arthritis, 1 sclerodermia) and 7 paraneoplastic DM (53 %). The cancers were located in: 2 breast, 2 lung, 1 colon, 1 stomach, and 1 ovary; they appeared either before (2 cases), at the same time (3 cases) or after the diagnosis of DM (2 cases). The organs clinically involved were: skin in 13 (100%), muscles in 12 (1 amyophatic), oesophagus in 2, and lungs in 1. The diagnostic tests performed were: muscular enzymes (CK / aldolase) in 100%, muscular biopsy in 3, skin biopsy in 5, and electromyography in 9. Autoantibodies were studied in patients, but were positive only in half (AAN in 6, ASMA in 2, anti-Mi2 in 1, anti-Jo in 1). Five patients received initially steroids, 7 dual therapy (corticosteroids and immunomodulators), and 1 monoclonal antibodies. At the time of this paper, only 3 patients are still alive. The survival after DM diagnosis in those who died varied between 21 days and 8 years, 6 were dying before ending the first year of diagnosis. Conclusions: The features of our series consistent with previous literature are gender distribution and association with the cancers more prevalent in general population. The facts that differ from literature are: •More cancers (53% vs 20–40%), with 2 cases of DM appearing only when the cancer relapsed. •Less interstitial lung disease (1 vs 30%). We wonder if we should always do a chest CT, instead of relying on a normal chest Rx to rule out this complication. •Lower survival rates at one year (40% vs 95%). We had one case of fulminant DM, dying 21 days after entering hospital for diagnosis. This variety of DM is related in recent publications to the novel autoantibody anti-MDA5. •Skin biopsies positive for DM in 100% of cases when performed. In our hospital we do them more often than muscular biopsies, due to technical issues. We suggest that skin biopsy, less aggressive that the muscular, is an alternative diagnostic test.