三例包涵体肌炎的临床与病理特点

目的探讨包涵体肌炎（ＩＢＭ）的临床与病理特点。方法总结３例ＩＢＭ病人的临床特点，并对肌活检标本进行酶组织化学、组织化学病理和超微病理研究。结果３例女性病人均在２４～３６岁发病，其临床特点为以双下肢无力起病，渐累及上肢，远端肢体受累常见。腱反射消失，血清肌酸激酶正常或轻度增高，肌活检光镜检查发现其主要病理改变为镶边空泡纤维，肌浆或肌核内有嗜酸性包涵体，肌内膜炎性细胞浸润和成群萎缩肌纤维。电镜观察发现３例均有肌浆内细丝或管状细丝包涵体，其中１例有核内包涵体。镶边空泡内含淀粉样细丝、髓样结构、絮状无结构物质和其他胞浆分解产物。肌核改变包括异染色质增多、核变大，核内包涵体及核崩解。结论电镜包埋、半薄切片定位是电镜下寻找包涵体并确诊ＩＢＭ的关键步骤。肌核改变可能是ＩＢＭ的病因基础，镶边空泡和肌浆内包涵体有可能来自于崩解的肌核。

A clinical and pathological study of 3 cases of inclusion body myositis

Objective The study was to investigate the clinical and pathological features of inclusion body myositis(IBM). Method Muscle biopsied specimens from the 3 patients with IBM were analyzed with histochemical and enzyme histochemical methods under light microscopy and electron microscopy. Results The 3 patients who were all females and aged from 24 to 36 years had an onset with lower limb weakness which ascended to involve the upper limbs. The distal weakness was usually as great as or even greater than the proximal weakness. Diminished or lost deep reflexes were found in all the 3 patients. Light microscopic examination showed that the rimmed vacuolated muscle fibers, the eosinophilic inclusions, atrophic fibers in groups and the inflammatory exudate within the endomysia constituted the cardinal pathological characteristics. Under the electron microscope, amyloid fibrils or tubulofilament inclusions in the cytoplasms were found in all 3 cases and intranuclear inclusions were found in only one case. Myonuclear alternations consisted of large nuclei, intranuclear inclusions, an excess of heterochromatin and myonuclear degradation. Conclusion Localization on semisection under the electron microscope might be the crucial procedure for finding the inclusions and making a definite diagnosis of IBM. Also the results suggested that myonuclear alterations might lead to the basic genesis of IBM.