Abstract
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 presentationAn 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 (SpO2 88%, pCO2 68 mmHg) and increased muscle enzyme levels (CPK 8479 U/L, AST 715 U/L, ALT 383 U/L, LDH 1795 U/L). The patient needed invasive mechanical ventilation. Inflammatory myositis was considered and treatment with intravenous methylprednisolone (30 mg/Kg/day for 3 days followed by 2 mg/Kg/day) and IVIG (1 g/kg/day for 2 days) was started. Muscle biopsy showed endomysial and perimysial necrosis and inflammation. The presence of serum anti-TIF1-γ antibody positivity led to a malignancy screening. Whole-body MRI showed a mature teratoma underneath sacral meningocele and both lesions were surgically removed.Given the histological and clinical severity of the myopathy, mycophenolate (500 mg twice a day) and rituximab (360 mg/m2, 4 weekly infusions) were added. Due to extreme muscular wasting, severe malnutrition and intolerance to enteral feeding the patient needed a transient tracheostomy and parenteral nutrition, followed by physiotherapy, speech therapy and nocturnal non-invasive ventilation. A complete remission was achieved 3 months after.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.
Highlights
Juvenile idiopathic inflammatory myopathies (JIIMs) are a group of heterogenous, acquired, autoimmune disorders that affect the muscle
Juvenile dermatomyositis (JDM) is the most recognizable and frequent, with an incidence of approximately 2.5 per million [1]; other forms of JIIMs, such as juvenile polymyositis (JP), immune-mediated necrotizing myositis (IMNM) and juvenile connective tissue diseaseassociated myositis (JCTM) are even rarer, and more difficult to identify compared to adult counterparts
While no significant difference was observed in the incidence of cancer among Idiopathic Inflammatory Myopathy (IIM) subgroups, recognized risk factors for cancer-associated myositis (CAM) include male gender, older age at disease onset, extensive skin or muscle involvement, elevated inflammatory markers, negative Antinuclear Antibodies (ANA) and/or Myositis Specific Autoantibodies (MSA) and, interestingly, antiSAE1, anti-Nuclear Matrix Protein-2 (NXP2), anti-Hydroxy-Methylglutaryl-Coenzyme A Reductase (HMGCR) and anti-Transcriptional Intermediary Factor 1 (TIF1)-γ antibodies positivity [10, 11], referred to as cancer associated autoantibodies (CAAs)
Summary
Among 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. 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
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have