Severe onset of inflammatory myositis in a child: think to paraneoplastic myositis.

backgroundJuvenile idiopathic inflammatory myopathies (JIIMs) are a group of heterogenous, acquired, autoimmune disorders that affect the muscle. While the association between IIMs and malignancy has been widely reported in adults, cancer-associated myositis (CAM) is rare in children, so that routine malignancy screening is not generally performed. This report shows a case of severe CAM in a child. CASE PRESENTATION: An 11-years-old girl presented with worsening dyspnea after a 3-weeks history of progressive proximal weakness, myalgia, dysphagia, and weight loss. Her past history was remarkable for a type I Arnold-Chiari malformation associated with an anterior sacral meningocele. Physical examination showed severe hypotony and hypotrophy. Pulse oximetry and blood test showed a type II respiratory failure (SpO

conclusionsAmong cancer-associated autoantibodies (CAAs) in adult patients, anti-TIF1-γ carries the highest risk of CAM, which recognizes with a high likelihood a paraneoplastic pathogenesis. In children, anti-TIF1-γ antibody has been associated with severe cutaneous disease, lipodystrophy, and chronic disease course, but not with CAM, which is overall rare in younger patients. Severe onset of a JIIM, especially if anti-TIF1-γ antibody positive, should prompt suspect of a CAM and lead to a screening for malignancy.