Analysis Of Ultrasonographic Characteristics Of Benign Thyroid Leisions Misdiagnosis As Thyroid Carcinoma:Sonographic-Pathologic Correlation

Objective:To analyze the ultrasonographic characteristics of benign thyroid lesions were misdiagnosed by ultrasonograpy and investigate the misdiagnosis reasons from the pathology in order to improve the accuracy of ultrasound in the diagnosis of benign thyroid lesions.Methods:From December 2012 to May 2014,Five hundred and seventy-eight patients with benign thyroid lesions underwent surgery and had histopathologic diagnosis at our hospital.The Thyroid Imaging Reporting and Data System(TI-RADS) lexicon was introduced to describe the lesions. With the pathology results as the basis, thirty-eight patients with forty-six nodules were misdiagnosed as thyroid cancer by ultrasonography, the pre-operative diagnosis of ultrasonography were retrospectively reviewed in light of their pathologic results.Results:With the five hundred and seventy-eight thyroid lesions, Thirty-eight cases were misdiagnosed as thyroid carcinoma by the pre-operative ultrasonography, the misdiagnosis rate was 6.6%. ① Forty-six nodules were divided into two grounps by the largest diameter,twenty-one thyroid nodules with a diameter of 10 mm or smaller, twenty-five nodules with a diameter of larger than 10 mm. In all forty-six benign thyroid nodules, the pre-operative diagnosis of ultrasonography showed the majority of nodules with 3 or more than 3malignant ultrasound finding.The forty-six benign thyroid nodules showed solid(89.1%,41/46), cystic-solid(10.9%, 5/46), marked hypoechogencity(87.0%, 40/46), ill-defined margin(56.5%, 26/46), calcification(76.1%, 35/46,microcalcification and macrocalcification), taller-than-wide shape(30.4%, 14/46). ②The thyroid imaging reporting and data system(TI-RADS) lexicon was introduced to describe the lesions:forty-one nodules were categorized as TI-RADS 4c and 5 nodules were categorized as TI-RADS 5,none was categorized as TI-RADS 1~3(normal thyroid or thyroiditis).③Pathological diagnosis of thirty-five cases with forty-five nodules were nodular goiter.One case with one nodule was thyroid atypical adenoma. Thyroid gland was diffuse change in two cases with no specific nodular, one case was subacute thyroiditis and another case was hashimoto’s thyroiditis.Histologic analysis of ultrasonographic misdiagnosis of benign thyroid lesions revealed severe fibrosis, even hyalinization and calcification. The ultrasonic images is complicated, and it was difficult to identify with the thyroid cancer.Conclusion:Benign thyroid lesions with histologically characterized by fibrosis with hyalinization,hemorrhage, calcification will make the corresponding change at morphology, echo intensity and the internal structure. When the benign and malignant signs of ultrasonic such as hypoechogencity or marked hypoechogencity, edge is regular or irregular,taller-than-wide shape appear at the same time or mix, benign thyroid nodules were misdiagnosed as thyroid cancer easily.