Late onset inflammatory myopathy associated with anti-Ro52 antibodies without lung involvement. Case report

Idiopathic inflammatory myopathies are a heterogeneous group of autoimmune diseases.Clinically they are characterized by symmetric muscle weakness and sometimes systemic involvement.They present neurophysiological and histological signs of chronic muscle inflammation, as well as elevation of muscle enzymes.Specific autoantibodies are useful biomarkers for diagnosis.We present the case of a patient with overlap myositis and positive anti-Ro52 antibodies without systemic activity at diagnosis.An 87-year-old woman with a history of basal cell carcinoma in the left malar region and hypothyroidism, both under control.Presented a progressive disease which began 6 months prior to the evaluation by our department, characterized by fatigue, weakness of proximal muscles in the four extremities, associated with myalgia in the pelvic girdle.Over the course of 2 months, showed difficulty performing instrumented activities of daily living.At the fifth month, she manifested dysphagia.On physical examination, symmetric weakness was documented, predominantly proximal, without alteration of the muscle stretch reflexes or sensory involvement.Laboratory analysis showed creatine phosphokinase elevation (2974 U/L).A panel of antibodies was made, finding anti-Ro52 +++.Body PET revealed hypometabolism in the proximal muscles of the four extremities, with no evidence of neoplastic activity.A muscle biopsy was performed, observing intrafascicular and perivascular inflammatory infiltrate, atrophy of perifascicular fibers.Management began with methylprednisolone pulses, presenting symptomatic improvement.The association of anti-Ro52 antibodies and dermatomyositis is rare, occurring in up to 26% in overlapping syndromes.Presentation with interstitial lung disease and cancer have a poor prognosis.