Among Idiopathic inflammatory myopathies, antisynthetase syndrome is meant to be rarely associated with cancer. However, clinical evidences of the association of those diseases led to the hypothesis that previous studies might have underestimated the prevalence of cancer in patients with antisynthetase syndrome. The aim of this study was to assess the prevalence of cancer in patients with antisynthetases syndrome in Grand Est and Bourgogne Franche-Comté regions.

Idiopathic inflammatory myopathies area heterogeneous group of disease involving mainly muscles, which paraneoplastic feature has been well characterized, specifically in some subgroups such as dermatomyositis. In contrast, antisynthetase syndrome is thought to be rarely associated with cancer. However, clinical observations of the association of those diseases led us to the hypothesis that previous studies might have underestimated the prevalence of cancer in patients with antisynthetase syndrome. The aim of this study was to assess the prevalence of cancer in patients with antisynthetases syndrome in Grand Est and Bourgogne Franche-Comté regions, describing the type of cancer observed as well as clinical features of patients and diagnostic work-up leading to the diagnosis of cancer.

Inclusion Criteria:

• adult patients
• positive antisynthetase antibodies (JO-1,PL12, PL17, EJ, OJ, KS, RS, YRS)

Exclusion Criteria:

• age under 18
• opposition to data collection
• no positive antisynthetase antibodies
• absence of clinical involvment

patients with antisynthetase syndrome, defined by the positivity of antisynthetase antibodies and the presence of at least one clinical involvment, are included, either with or without cancer, to allow comparison of patients according to the presence of cancer.