Clinical And Pathological Features Of Papillarythyroid Carcinoma With Hashimoto Thyroiditis And The Risk Factors For Its Lymph Node Metastasis

Objective:Papillary thyroid carcinoma(PTC)and Hashimoto thyroiditis(HT)have been increasing in recent years.Incidence of PTC with HT(HTPTC)is also on the rise.The purpose of this study was aimed to investigate the clinical and pathological characteristics of HTPTC,including the regularity of neck lymph node metastasis,and to provide a valuable reference for the clinical diagnosis and treatment of HTPTC.Method:According to relevant inclusion and exclusion criteria,altogether248 patients with PTC were selected for this study,who were firstly diagnosed and received standard treatment in our hospital from January 2014 to December2018.A retrospective analysis was made on age,sex,single and multiple lesions,bilateral gland involvement,maximum diameter,capsular invasion,preoperative thyroid timulating hormone(TSH),T classifiation,central lymph node metastasis and lateral necklymph node metastasis.SPSS statistical software was used to analyze the differences of the above indicators between HTPTC and those PTC without HT,including central lymph node metastasis and lateral necklymph node metastasis.Result:The 248 PTC patients were newly diagnosed by frozen section pathology during operation and routine pathology after operation.The 203patients with PTC without HT included 150 women(73.9%)and 53 men(26.1%),withhe median age,the median tumor length and the median preoperative TSH being 40 years,1.30 cm and 1.44μIU/ml respectively,Sixty-five cases(32.0%)were with papillary thyroid microcarcinoma(PTMC),and 64 cases(31.5%)had multiple primary lesions.In addition,capsular invasion were indicated in 46 cases(22.7%).With the aspect to lymphatic involvement,102 cases(50.2%)had central cervical lymph node metastasis,and 45 cases(22.3%)had lateral cervical lymph node metastasis.Forty-five patients with HTPTC included 42 females(93.3%)and 3males(6.7%),with the median age,the median tumor longest diameter and themedian preoperative TSH being 40 years,1.25cm and 1.78uIU/ml,respectively.Seventeen(37.8%)cases were with PTMC and 16 cases(35.6%)and 6 cases(13.3%)had multiple lesionsand capsular invasion respectively.central lymph node metastasiswas in 14 cases(31.1%),and lateral neck lymph node metastasis wasin 5 cases(11.1%).Compared with patients of PTC without HT,the proportion of female with HTPTC was significantly higher(93.3%vs 73.9%,P=0.003).The rate of lymph node metastasis in central region was significantly lower among HTPTC patients than that among the PTC patients without HT(31.1%vs 50.2%,P=0.021).There was no significant difference of lateral neck lymph node metastasis(11.1%vs 22.3%,P=0.094),age(42.29±12.01 vs 40.99±12.74,P=0.534),tumor longest diameter s[1.250(1.000,1.600)vs 1.300(1.100,1.500),P=0.734]between HTPTC patients and the PTC patients without HT.there was also no significant difference in the proportion of multiple primary tumors(35.6%vs 31.5%,P=0.534),percentage of encapsulated invaders(13.3%vs 22.7%,P=0164)and the median preoperative TSH level[1.780(1.250,2.155)vs 1.440(1.221,1.650),P=0.221]between these two groups.Multivariate analysis of lymph node metastasis showed that HT[OR=0.393,95%CI=(0.179-0.865),P=0.020],PTMC(tumor length≤1cm)[OR=0.232,95%CI=0.116-0.463,P<0.001]and age<44 years[OR=0.383,95%CI=(0.205-0.717),P=0.003]may be,may be independent protective factors for lymph node metastasis in the central cervical region.,Bilateral thyroid gland involvement may be a risk factor for lymph node metastasis in the central region inPTC[OR=2.503,95%CI=(1.049-5.951),P=0.039].For lymph node metastasis in the lateral neck region,PTMC(tumor length≤1cm)[OR=0.356).95%CI=(0.151-0.882),P=0.025]was shown tobe a protective factor,,and however,TSH(>1.42 uIU/ml)before operation was shown to bearisk factor[OR=2.421,95%CI=(1.191-4.921),P=0.015].We also analyzed those with metastatic lymph node in bothgroup of HTPTC and PTC without HT,and found a lower proportion of metastatic lymph node aomong those lymph nodes dissected in the central region in the HTPTC group,compare with that in the group of PTC without HT(X~2=16.04,P<0.001).Nevertheless,there was no significant difference of the metastatic lateral lymph node proportion of between these two groups(X~2=0.083,P=0.774).Conclusion:In the population of HTPTC,the proportion of females may be higher than that of PTC without HT;The rate of lymph node metastasis in the central region of HTPTC patients may be lower than that ofthose PTC patients without,and HT may be a protective factor decreasing lymphatic metastasis risk in the central region of PTC;Among those PTC patients with lymphatic metastasis,the proportion of metastatic lymph nodeamong those removed lymph nodes in the central neck dissection may be lower than that of those PTC patients without HT.