[Inflammatory myofibroblastic tumour of thyroid: a case report].

: A elderly woman patient，with a unclear boundary,solid,smooth surface,moderately active mass that estimated 0.4 cm at its greatest diameter in the left lobe of thyroid. Ultrasonography revealed a hypoechoic mass in the left lobe and Computed Tomography showed a 38 mm×25 mm×23 mm oval lesion with uniform density in the left lobe also. The surgical findings revealed tumor located in the inner side of left thyroid lobe near the isthmus,with unclear boundary. Pathological examination showed unclear boundaries between thyroid and tumor,the tumor cells attack into the muscle tissue,braided/ fascicles spindle shaped or star shaped myofibroblasts cells in the tumor area with myxedema inflammatory background and the lesion did not have any mitotic figures. Immunohistochemical analysis indicated that the spindle cells were positive for Vim,ACT,SMA,Bcl2 and ClyD1,and focal lesion histiocytes showed focal positive for CD68,CK and S-100,but negative for DES,Mgo,CD99,CD34,CD117,IgG4,ALK-1.The pathological diagnosis supports inflammatory myofibroblastic tumor of thyroid. Imaging and immunohistochemistry and others are useful in differential diagnosis.