Paraneoplastic Inflammatory Myositis False-positive for Anti-aminoacyl-tRNA synthetase Antibody Successfully Ameliorated by Immunosuppressive Therapy
We herein report a 60-year-old woman with anti-aminoacyl-tRNA synthetase (ARS) antibody-false-positive paraneoplastic polymyositis complicated with ovarian carcinoma, which was promptly ameliorated by immunosuppressive therapy, including glucocorticoids (GCs), before treatment against malignancy. The patient was admitted to our hospital because of rapidly progressive muscular weakness of the neck and both limbs over three weeks. Upon a detailed examination, the patient tested positive for anti-ARS antibodies by an enzyme-linked immunosorbent assay (ELISA), which were later determined to be false positives, as confirmed by immunoblotting and immunoprecipitation. She was strongly suspected to have ovarian carcinoma and pulmonary metastasis. A biopsy of her muscle revealed myositis, mainly with CD68