Study of the histological profile of papillary thyroid carcinomas associated with Hashimoto's thyroiditis

Clinical and molecular impact of concurrent thyroid autoimmune disease and thyroid cancer: From the bench to bedside

The recent incorporation of immune checkpoint inhibitors targeting the PD-1 (programmed cell death receptor 1) and CTLA-4 (cytotoxic T lymphocyte antigen 4) pathways into the therapeutic armamentarium of cancer has increased the need to understand the correlation between the immune system, autoimmunity, and malignant neoplasms. Both autoimmune thyroid diseases and thyroid cancer are common clinical conditions. The molecular pathology of autoimmune thyroid diseases is characterized by the important impact of the PD-1/PD-L1 axis, an important inhibitory pathway involved in the regulation of T-cell responses. Insufficient inhibitory pathways may prone the thyroid tissue to a self-destructive immune response that leads to hypothyroidism. On the other hand, the PD-1/PD-L1 axis and other co-inhibitory pathways are the cornerstones of the immune escape mechanisms in thyroid cancer, which is a mechanism through which the immune response fails to recognize and eradicate thyroid tumor cells. This common mechanism raises the idea that thyroid autoimmunity and thyroid cancer may be opposite sides of the same coin, meaning that both conditions share similar molecular signatures. When associated with thyroid autoimmunity, thyroid cancer may have a less aggressive presentation, even though the molecular explanation of this clinical consequence is unclear. More studies are warranted to elucidate the molecular link between thyroid autoimmune disease and thyroid cancer. The prognostic impact that thyroid autoimmune disease, especially chronic lymphocytic thyroiditis, may exert on thyroid cancer raises important insights that can help physicians to better individualize the management of patients with thyroid cancer.

Association between Hashimoto thyroiditis and clinical outcomes of papillary thyroid carcinoma: A meta-analysis

Objective

To assess association between Hashimoto thyroiditis (HT) and clinical outcomes of papillary thyroid carcinoma (PTC).

Methods

Databases including Pubmed, Embase, Cochrane Library, and Web of Science were searched. Weighed mean differences (WMDs) and odds ratios (ORs) were used to evaluate association between HT and clinical outcomes of PTC, and the effect size was represented by 95% confidence intervals (CIs). Heterogeneity test was performed for each indicator. If the heterogeneity statistic I²≥50%, random-effects model analysis was carried out, otherwise, fixed-effect model analysis was performed. Sensitivity analysis was performed for all outcomes, and publication bias was tested by Begg’s test.

Results

Totally 47,237 patients in 65 articles were enrolled in this study, of which 12909 patients with HT and 34328 patients without HT. Our result indicated that PTC patients with HT tended to have lower risks of lymph node metastasis (OR: 0.787, 95%CI: 0.686–0.903, P = 0.001), distant metastasis (OR: 0.435, 95%CI: 0.279–0.676, P<0.001), extrathyroidal extension (OR: 0.745, 95%CI: 0.657–0.845, P<0.001), recurrence (OR: 0.627, 95%CI: 0.483–0.813, P<0.001), vascular invasion (OR: 0.718, 95%CI: 0.572–0.901, P = 0.004), and a better 20-year survival rate (OR: 1.396, 95%CI: 1.109–1.758, P = 0.005) while had higher risks of multifocality (OR: 1.245, 95%CI: 1.132–1.368, P<0.001), perineural infiltration (OR: 1.922, 95%CI: 1.195–3.093, P = 0.007), and bilaterality (OR: 1.394, 95%CI: 1.118–1.739, P = 0.003).

Conclusions

PTC patients with HT may have favorable clinicopathologic characteristics, compared to PTCs without HT. More prospective studies are needed to further elucidate this relationship.

Hashimoto's Thyroiditis: A "Double-Edged Sword" in Thyroid Carcinoma

BACKGROUND

The prevalence of thyroid carcinoma (TC) and Hashimoto's thyroiditis (HT) has been increasing dramatically over the past decades. We investigated the relationship between HT and TC.

METHODS

We followed the Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines for carrying out and reporting this meta-analysis. The literature from January 1, 2010 to December 31, 2020, regardless of region and publication type, was searched comprehensively in PubMed, Embase, Web of Science, and Cochrane Library databases. After careful selection and data extraction, the pooled odds ratio of various clinical characteristics in 39 studies were calculated. Publication bias was analyzed using funnel plots.

RESULTS

Meta-analysis of 39 original research articles showed HT to be a risk factor of TC (pooled odds ratio = 1.71; 95% confidence interval, 1.57-1.80; p < 0.00001) and papillary thyroid carcinoma (1.67, 1.51-1.85, <0.00001). Patients with papillary thyroid carcinoma (PTC) combined with HT were more likely to have multifocal carcinomas. The prevalence of an extrathyroidal extension, metastasis, BRAF^V600E mutation, and recurrence was significantly lower in patients with PTC combined with HT.

CONCLUSIONS

HT is a "double-edged sword" in TC patients. HT increases the risk of TC and PTC but is a protective factor against PTC progression.

Association between Thyroiditis and Multifocality in Papillary Thyroid Carcinoma

Introduction  Hashimoto thyroiditis (HT) shares many characteristics with papillary thyroid carcinoma (PTC), and some studies show that, when associated, PTC is diagnosed mostly with smaller lesions and multifocal pattern.

Objective  To evaluate the relationship between HT and PTC.

Methods  A retrospective study of 155 patients who underwent total thyroidectomy from 2009 to 2015. Demographical, clinical and ultrasonographical data, as well as anatomopathological findings were evaluated.

Results  There were signs of thyroidits in 35 patients, and 114 patients had a unifocal disease. There was no statistical significance between the variables studied and thyroiditis. However, when compared with the occurrence of unifocal or multifocal lesions, there was statistical significance regarding age ( p  = 0.038) and mass ( p  = 0.031). There was no direct relationship between thyroiditis and multifocality ( p  = 0.325) nor between thyroiditis and cervical extension of the disease ( p  = 0.300 e p  = 0.434).

Conclusion  There was no relationship between thyroiditis and multifocality in cases of PTC.

Lymph node metastasis around the entrance point to recurrent laryngeal nerve in papillary thyroid carcinoma

There are few reports on the lymph nodes of entrance point to recurrent laryngeal nerve (LN-epRLN) in patients with papillary thyroid carcinoma (PTC). Thus, we investigated the clinical significance of LN-epRLN and implications it may have. An observational analysis of 878 consecutive patients with PTC who underwent thyroidectomy from April 2016 to March 2017 was conducted. We explored the surrounding tissue of laryngeal entry point, during routine central lymph node dissection (CLND). The lymph node specimens were sent separately for routine histopathological examination. Thereafter, complications and follow-ups were recorded. LN-epRLNs were found in 73 of the 878 patients, with the metastatic rate of 3.76%. Univariate and multivariate analysis showed central lymph node metastases can serve as independent predictors for LN-epRLN metastasis. In summary, we confirmed the significance of LN-epRLN in metastasis and recurrence, which required precise anatomy and thorough CLND. In PTC patients, especially in suspicious presence of central cervical lymph node metastasis, attention should be given to excising the nodal tissue at the laryngeal entry point.

Thyroid cancer associated with Hashimoto thyroiditis: similarities and differences in an endemic area

BACKGROUND

Hashimoto thyroiditis (HT) is an autoimmune lymphocytic thyroiditis and is the most common form of thyroid inflammatory diseases. The association of HT with papillary thyroid carcinoma (PTC) has been described. PTC is the most common form of malignancy associated with HT. When papillary carcinoma develops on top of Hashimoto thyroiditis, the disease tends to be less aggressive and lymph node and extra-thyroidal invasion are infrequent.

RESULTS

We retrospectively examined the pathological features of our patients who were diagnosed with concomitant HT and thyroid cancer. In Egyptian patients, PTC was the main type of malignancy associated with HT (96.2%) and was often multifocal (46.2%). In contrast to the published literature, lymph node invasion and extra-thyroidal extension were as frequent in association with HT as in other cancer cohorts. We also observed the frequent occurrence of Hürthle cell metaplasia (23.1%) and the appreciable incidence of aggressive histological types of PTC (32%).

CONCLUSION

Thyroid carcinoma with HT may have some aggressive features in areas with endemic goiter background.

Associations between Hashimoto Thyroiditis and Clinical Outcomes of Papillary Thyroid Cancer: A Meta-Analysis of Observational Studies

BACKGROUND

Epidemiological studies have suggested an association between Hashimoto thyroiditis (HT) and papillary thyroid cancer (PTC) development. Other studies, however, have reported a protective role of HT against PTC progression. Through this updated meta-analysis, we aimed to clarify the effects of HT on the progression of PTC.

METHODS

We searched citation databases, including PubMed and Embase, for relevant studies from inception to September 2017. From these studies, we calculated the pooled odds ratios (ORs) of clinicopathologic features and the relative risk (RR) of PTC recurrence with 95% confidence intervals (CIs) using the Mantel-Haenszel method. Additionally, the Higgins I² statistic was used to test for heterogeneity.

RESULTS

The meta-analysis included 71 published studies with 44,034 participants, among whom 11,132 had HT. We observed negative associations between PTC with comorbid HT and extrathyroidal extension (OR, 0.74; 95% CI, 0.68 to 0.81), lymph node metastasis (OR, 0.82; 95% CI, 0.72 to 0.94), distant metastasis (OR, 0.49; 95% CI, 0.32 to 0.76), and recurrence (RR, 0.50; 95% CI, 0.41 to 0.61).

CONCLUSION

In this meta-analysis, PTC patients with HT appeared to exhibit more favorable clinicopathologic characteristics and a better prognosis than those without HT.

Histopathological Evidence of Lymph Node Metastasis in Papillary Thyroid Carcinoma

Prophylactic lymph node dissection is still controversial due to the potentially surgery-related morbidity in management of papillary thyroid carcinomas. So, some histopathological predictors for lymph node metastasis in thyroidectomy specimens may reveal importance. The objective of this study was to define histomorphological indicators of lymph node metastasis in the patients who had been performed thyroidectomy without lymph node dissection. Clinicopathological features of patients archived in Department of Pathology at Trakya University Medical Faculty were reviewed. A total of 211 patients who had been diagnosed as papillary carcinoma and had been performed total thyroidectomy/lobectomy with central/cervical lymph node dissection were included in the study. Clinical features (age, gender, preoperative/postoperative clinical, and laboratory findings) and histopathological features (histological variant, tumor size, focality, extrathyroidal extension, tumor border, lateral tubular growth, intraglandular dissemination, stromal and lymphocytic tumor response, lymphocytic thyroiditis, lymphovascular invasion, lymph node metastasis, number of metastatic lymph nodes, extranodal extension, size of the metastatic foci) were evaluated. Male gender, conventional variant, tumor size greater than 10 mm, multifocality, extrathyroidal extension, lateral tubular growth, intraglandular dissemination, lymphocytic and stromal tumor response, and absence of lymphocytic thyroiditis were predictive, and older age (≥45 years) and follicular variant PTC were protective for lymph node metastasis. In order to optimize the management of papillary thyroid carcinomas, pathologists should search for the clues of lymph node metastasis particularly intraglandular dissemination, lateral tubular growth, tumor border and lymphocytic/stromal tumor response, multifocality, concomitant lymphocytic thyroiditis besides the actual prognostic criteria especially in younger aged male patients.