结节型肌肉结节病MRI表现与病理对照研究

Nodular muscular sarcoidosis： MRI manifestation and pathological features

目的对比分析结节型肌肉结节病的MRI影像表现与病理表现，探讨肌肉结节病的MRI影像特征，提高对肌肉结节病的影像诊断的认识。方法收集宁波市第二医院及浙江省人民医院2012年3月至2017年1月经病理证实的结节型肌肉结节病6例，回顾分析其MRI影像资料、手术所见、病理表现，并结合文献资料对其MRI影像特征进行讨论。结果3例为一侧小腿腓肠肌单个病灶，1例为一侧大腿前内侧肌多个病灶，2例为两侧小腿腓肠肌多个病灶；6例患者均行MRI平扫及增强检查；MRI平扫均表现为沿肌纤维走行的条状或梭形略短TI长T2信号，占位效应不明显，横断位T2WI和增强T1WI病灶中心呈“黑色星芒征”，沿病灶长轴切面图像可见“三层条纹征”；增强后实质强化明显，中心轻度强化；5例较大病灶周围可见类似小结节样卫星病灶，4例在远处肌群可见类似小结节强化影。病理表现：肌纤维、肌问见上皮细胞、多核组织细胞集聚的肉芽肿性炎，伴或不伴淋巴细胞浸润；结节内未见干酪样坏死，结节可见融合。结论MRI上表现为沿肌纤维走形条状或梭形病灶、可见“三层条纹征”和“黑色星芒征”、周围肌群可见强化小结节的特征，有助于对结节型肌肉结节病的诊断和鉴别诊断。

Objective To analyze the MR imaging performances and pathological characteristics of nodular muscular sarcoidosis, and to improve the diagnostic accuracy. Methods Six cases with pathologically confirmed nodular muscular sarcoidosis were included, the MRI imaging findings and pathologic appearance were analyzed, and the hterature was reviewed. Results Six patients underwent plain and enhanced MRI examination with 3 cases of unilateral gastrocnemius muscle single lesion, 1 case of unilateral anterior medial thigh muscle lesions, and 2 cases of bilateral gastrocnemius muscle lesions. MRI plain scan showed a strip-shaped or fusiform with slightly short TI-long T2 signal along the muscle fibers, and the occupancy effect was not obvious. ＂Dark star＂ sign showed in lesion center with axial T2WI and enhanced T1WI,and ＂three stripes＂ sign could be seen along the long axis view image lesions. The lesion obviously enhanced after enhancement, with mild enhancement center. Similar small nodular satellite lesions were seen around 5 large lesions, and 4 cases showed similar small nodule enhancement in distant muscle groups. Pathological manifestations： granulomatous inflammation of muscle fibers, intermuscular epithelial cells, and multinucleated tissue ceils with or without lymphocytic infiltration; no cheese-like necrosis in the nodules, visible fusion of nodules. Conclusion On MRI, it is characterized by strips or fusiform lesions along the muscle fibers, visible ＂three-layer stripe sign＂ and ＂black star sign＂, and the characteristics of the enhanced muscle nodules in the surrounding muscle groups, which contributes to the diagnosis and differential diagnosis of muscular sarcoidosis.