DERMATOMYOSITIS SINE MYOSITIS - ASSOCIATION WITH MALIGNANCY

Objective, To describe dermatomyositis (DM) sine myositis as a distinc t diagnostic subclass of DM and the association with malignancy. Metho ds, This case series includes all patients presenting to our primary a nd tertiary care outpatient dermatology department with DM and DM sine myositis between 1986 and 1993. Seven patients were diagnosed with cl assic DM and 12 with DM sine myositis. We analyzed average age of onse t, duration of followup, clinical course, and incidence of associated malignancy in the patients with classic DM and DM sine myositis. Resul ts, No statistically significant differences were found in these 2 gro ups on examining age at onset and frequency of associated malignancy. Malignancy was diagnosed in 4 of 12 (25%) patients with DM sine myosit is followed for a total of 50.8 patient-years (average followup 51 mon ths) and in 2 of 7 (28%) patients with classic DM followed for a total of 20.6 patient-years (average followup 35 months). Conclusion. Altho ugh these patients with DM are select and few, they demonstrate that D M sine myositis may be quite similar to classic DM. It may be said tha t like DM, DM sine myositis may represent a paraneoplastic syndrome. D M sine myositis should be added to the currently accepted polymyositis /dermatomyositis classification system, with appropriate emphasis on t he potential association with malignancy.