Factors of color ultrasound diagnosis of false negative thyroid cancer: an analysis of 176 cases        WANG Hai-ling, ZHANG Sheng, XIN Xiao-jie, et al. Department of Ultrasound Diagnosis and Treatment, Tianjin Medical University Cancer Institute and Hospital, Tianjin300060, China
Corresponding author: WANG Hai-ling, E-mail:whailing2226666@yahoo.cn
Abstract    Objective    To study the factors of color Doppler ultrasound diagnosis of 176 cases of false negative thyroid cancer and to evaluate the clinical, radiological and histological features of false negative results. Methods    The data of 1466 cases of primary thyroid cancer confirmed by pathology between 2007 and 2009 at Tianjin Medical University Cancer Institute and Hospital were analyzed retrospectively. The clinical, imageology and histopathological differences between 176 preoperative false negative cases and 1290 true positive cases were compared. Results    (1) The age of false-negative group and true positive group were 45.7 ± 11.6 and 43.9 ± 13.4 years old respectively. There was no significant difference between two groups. (2) The false negative group was often associated with nodular goiter or Hashimoto's thyroiditis. (3) The proportion of microcarcinoma in false negative group was greater than that in true positive group. (4) The false negative group was less associated with cervical metastatic lymph nodes compared with the true positive group. (5) The proportion of follicular carcinoma in the false negative group was more than that in true positive group. The proportion of diffuse sclerosing variant of papillary carcinoma in the false negative group was less than that in the true positive group. Conclusion    False negative thyroid cancer cases diagnosed by ultrasound is often associated with other diseases. Smaller tumor size, less associated with cervical lymph node metastasis, histological type and subtypes have certain characteristics. When there is clinical suspicion, the diagnosis should be further clarified, so as not to delay treatment.