A 54-year-old woman developed drop head syndrome (DHS), Raynaud's phenomenon and creatine kinase (CK) elevation. She did not meet the international classification criteria of dermatomyositis/polymyositis, as we observed no muscle weakness, grasping pain or electromyography abnormality in her limbs, and anti-aminoacyl tRNA synthetase (ARS) antibody was negative. Cervical magnetic resonance imaging and a muscle biopsy of the trapezius muscle revealed myositis findings as the only clinical observations in muscle. These findings, along with her anti-U1-ribonucleoprotein (RNP) antibody positivity and leukopenia, resulted in a diagnosis of mixed connective tissue disease (MCTD). Prednisolone treatment significantly improved her myositis. To our knowledge, this is the first report of DHS as the only muscle complication of MCTD.
Keywords: drop head syndrome; mixed connective tissue disease; myositis; neck extensor muscles.