The Impact of Hashimoto Thyroiditis on Thyroid Nodule Cytology and Risk of Thyroid Cancer

Abstract

Context The impact of Hashimoto thyroiditis (HT) on the risk of thyroid cancer and its accurate detection remains unclear. The presence of a chronic lymphocytic infiltration imparts a logical mechanism potentially altering neoplastic transformation, while also influencing the accuracy of diagnostic evaluation. Methods We performed a prospective, cohort analysis of 9851 consecutive patients with 21,397 nodules ≥1 cm who underwent nodule evaluation between 1995 and 2017. The definition of HT included (i) elevated thyroid peroxidase antibody (TPOAb) level and/or (ii) findings of diffuse heterogeneity on ultrasound, and/or (iii) the finding of diffuse lymphocytic thyroiditis on histopathology. The impact of HT on the distribution of cytology and, ultimately, on malignancy risk was determined. Results A total of 2651 patients (27%) were diagnosed with HT, and 3895 HT nodules and 10,168 non-HT nodules were biopsied. The prevalence of indeterminate and malignant cytology was higher in the HT vs non-HT group (indeterminate: 26.3% vs 21.8%, respectively, P < 0.001; malignant: 10.0% vs 6.4%, respectively, P < 0.001). Ultimately, the risk of any nodule proving malignant was significantly elevated in the setting of HT (relative risk, 1.6; 95% CI, 1.44 to 1.79; P < 0.001), and was maintained when patients with solitary or multiple nodules were analyzed separately (HT vs non-HT: 24.5% vs 16.3% solitary; 22.1% vs 15.4% multinodular; P < 0.01). Conclusion HT increases the risk of thyroid malignancy in any patient presenting for nodule evaluation. Diffuse sonographic heterogeneity and/or TPOAb positivity should be used for risk assessment at time of evaluation.

Hashimoto's Thyroiditis Is a Risk Factor for Thyroid Cancer

“…This is a prospective cohort study of 10,054 consecutive adult patients with thyroid nodules >1 cm who were evaluated between 1995 and 2017 at the Brigham and Women's Hospital Thyroid Nodule Clinic (3). All patients underwent sonographic and clinical assessment.…”

False-Positive Malignant Diagnosis of Nodule Mimicking Lesions by Computer-Aided Thyroid Nodule Analysis in Clinical Ultrasonography Practice

“…Thyroiditis related focal inhomogeneity appeared to be a differential diagnostic entity related to systematic CAD system misdiagnosis, i.e., false-positive detection, since the CAD system appreciated them as a nodule and almost always assigned them a K-TIRADS score of 5 due to "ill-defined borders" and "hypoechogenicity". In clinical practice, especially with less experienced users, such false-positive misdiagnoses may lead to high rates of unnecessary FNAB indications, keeping the high incidence of chronic thyroiditis in mind [42,43].…”

“…To cite an example, the differentiation of a nodule from a pseudonodule or focal parenchymal inhomogeneity may be challenging in chronic or subacute thyroiditis [37][38][39][40][41]. This, in turn, is a very common and important clinical problem, since autoimmune thyroiditis has a very high (up to 20%) prevalence and is also widely believed to pose a higher risk regarding thyroid malignancies [42,43].…”

Bioinformatics analysis of key genes and pathways in Hashimoto thyroiditis tissues

“…Silva et al performed a prospective, cohort study containing 9851 consecutive patients with 21,397 nodules, and they found that the malignant risk of nodules in HT patients is 1.6 times higher than that in non-HT patients. Another study has shown that HT leads to a 3-fold increase in malignant risk compared with non-HT thyroid diseases and that the lymph node metastasis risk is four times greater than that in non-HT patients [ 12 , 13 ]. Therefore, blockade of HT at the source has important significance on decreasing prevalence and progression of thyroid cancer.…”