title: A case of anti-nuclear matrix protein 2 antibody positive myopathy associated with lung cancer.
abstract: Myositis-specific autoantibodies (MSAs) are associated with myositis. Anti-nuclear matrix protein 2 (NXP-2) antibody was recently identified as a major MSA and was observed mostly in juvenile dermatomyositis. We report the case of a 44-year-old man who presented with myopathy with anti-NXP-2 antibody and large cell carcinoma of the lung. He was hospitalized because of myalgia and edema of limbs. Neurological examination revealed mild proximal-dominant weakness in all four extremities, and laboratory studies showed elevated creatine kinase level (6,432 IU/l). Needle electromyography showed myogenic patterns. MRI of the lower limbs demonstrated inflammatory lesions in the thighs. Biopsied specimen from the left quadriceps femoris muscle showed mild mononuclear inflammatory infiltrate surrounding muscle fibres but no fiber necrosis. He was diagnosed with myopathy based on neurological examinations and clinical symptoms. His chest X-ray and CT showed tumor shadow on the right upper lung field, but CT didn't indicate the findings of interstitial lung disease. This was surgically removed, and a histological diagnosis of non-small cell lung cancer was suspected. He was also treated with definitive chemoradiotherapy before and after operation. His symptoms of myopathy promptly remitted with the preoperative chemotherapy. His serum analysis was positive for the anti-NXP-2. Further investigation and experience of MSAs are necessary to evaluate the therapeutic strategy against cancer-associated myopathy/myositis.
authors.affiliation: Division of Neurology, Department of Internal Medicine I, Osaka Medical College.
authors.forename: Shin
authors.initials: S
authors.lastname: Ohta
authors.forename: Ki-Ichi
authors.initials: K
authors.lastname: Unoda
authors.forename: Hideto
authors.initials: H
authors.lastname: Nakajima
authors.forename: Soichiro
authors.initials: S
authors.lastname: Ikeda
authors.forename: Yasuhito
authors.initials: Y
authors.lastname: Hamaguchi
authors.forename: Fumiharu
authors.initials: F
authors.lastname: Kimura
mesh_terms: D000251:Adenosine Triphosphatases / Q000276:immunology*; D000328:Adult; D001323:Autoantibodies; D018287:Carcinoma, Large Cell / Q000150:complications* / Q000175:diagnosis / Q000628:therapy; D059186:Chemoradiotherapy, Adjuvant; D003131:Combined Modality Therapy; D004268:DNA-Binding Proteins / Q000276:immunology*; D006801:Humans; D008175:Lung Neoplasms / Q000150:complications* / Q000175:diagnosis / Q000628:therapy; D008279:Magnetic Resonance Imaging; D008297:Male; D009220:Myositis / Q000175:diagnosis / Q000209:etiology* / Q000276:immunology* / Q000628:therapy; D011013:Pneumonectomy; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D001323:Autoantibodies; D004268:DNA-Binding Proteins; D000251:Adenosine Triphosphatases; C551732:MORC3 protein, human