Acciavatti Angela, Avolio Tiziana, Rappuoli Simone, Foderi Luca, Soldati Vittoria, Franchi Massimo, Volpi Nila, Nuti Ranuccio
Department of Internal Medicine, University of Siena, Viale Bracci, 53100, Siena, Italy.
J Med Case Rep. 2013 Apr 25;7:112. doi: 10.1186/1752-1947-7-112.
Inflammatory myopathies (such as dermatomyositis and polymyositis) are well-recognized paraneoplastic syndromes. However, paraneoplastic necrotizing myopathy is a more recently defined clinical entity, characterized by rapidly progressive, symmetrical, predominantly proximal muscle weakness with severe disability, and associated with a marked increase in serum muscle enzyme levels. Paraneoplastic necrotizing myopathy requires muscle biopsy for diagnosis, which typically shows massive necrosis of muscle fibers with limited or absent inflammatory infiltrates.
We report the case of an 82-year-old Italian-born Caucasian man who was admitted to hospital because of heart failure and two drop attacks. Over the following days, he developed progressive severe weakness, dysphagia, and dysphonia. Testing showed increasing serum muscle enzyme levels. Electromyography showed irritative myopathy of the proximal muscles and sensorimotor polyneuropathy. Muscle biopsy (left vastus lateralis) showed massive necrosis of muscle fibers with negligible inflammatory infiltrates, complement membrane attack complex deposition on endomysial capillaries, and moderate upregulation of major histocompatibility complex-I. Computed tomography of the thorax showed a nodular mass in the apex of the right lung. The patient was diagnosed with paraneoplastic necrotizing myopathy. In spite of high-dose corticoid therapy, he died 1 month later because of his aggressive cancer. Subsequent electron microscopic examination of a muscle biopsy specimen showed thickened walls and typical pipestem changes of the endomysial capillaries, with swollen endothelial cells. Poorly differentiated adenocarcinoma of the lung was confirmed on post-mortem histological examination.
Paraneoplastic necrotizing myopathy is a rare syndrome with outcomes ranging from fast progression to complete recovery. Treatment with corticosteroids is often ineffective, and prognosis depends mainly on the characteristics of the underlying cancer. This case shows that paraneoplastic necrotizing myopathy may have an atypical appearance, and should be considered in elderly patients with neoplastic disease. In this case, the diagnosis was delayed by the unusual clinical picture that suggested heart disease rather than muscle disease.
炎性肌病（如皮肌炎和多发性肌炎）是公认的副肿瘤综合征。然而，副肿瘤性坏死性肌病是一种较新定义的临床实体，其特征为快速进展的、对称性的、主要累及近端肌肉的无力且伴有严重残疾，并伴有血清肌酶水平显著升高。副肿瘤性坏死性肌病需要进行肌肉活检以确诊，活检通常显示肌纤维大量坏死，炎症浸润有限或无炎症浸润。
我们报告一例82岁出生于意大利的白种男性，因心力衰竭和两次跌倒发作入院。在接下来的几天里，他出现了进行性严重无力、吞咽困难和发音困难。检查显示血清肌酶水平升高。肌电图显示近端肌肉刺激性肌病和感觉运动性多神经病。肌肉活检（左股外侧肌）显示肌纤维大量坏死，炎症浸润可忽略不计，补体膜攻击复合物沉积于肌内膜毛细血管，主要组织相容性复合体-I中度上调。胸部计算机断层扫描显示右肺尖有一个结节状肿块。该患者被诊断为副肿瘤性坏死性肌病。尽管接受了大剂量皮质类固醇治疗，但他1个月后因侵袭性癌症死亡。随后对肌肉活检标本进行电子显微镜检查显示肌内膜毛细血管壁增厚和典型的管状改变，内皮细胞肿胀。尸检组织学检查证实为低分化肺腺癌。
副肿瘤性坏死性肌病是一种罕见综合征，其转归范围从快速进展到完全恢复。皮质类固醇治疗通常无效，预后主要取决于潜在癌症的特征。本病例表明，副肿瘤性坏死性肌病可能有非典型表现，在患有肿瘤疾病的老年患者中应予以考虑。在本病例中，由于提示心脏病而非肌肉疾病的不寻常临床表现，诊断被延迟。
