Nodular muscular sarcoidosis: MRI manifestation and pathological features / 中华内分泌外科杂志

ABSTRACT

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 literature 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 manifestationsgranulomatous inflammation of muscle fibers,intermuscular epithelial cells,and multinucleated tissue cells 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.