Thyroid autoimmunity and throid tumors: results of a echographic, cytological and histological study.

OBJECTIVE: The association between chronic lymphocytic thyroiditis or Hashimoto’s thyroiditis (HT) and papillary thyroid carcinoma (PTC) has been suggested by surgical studies, but it is difficult to prove due to the contrasting results obtained with different methodological approaches. Aim of this study was to evaluate the association between HT and thyroid neoplasias comparing several diagnostic parameters by an univariate analysis. PATIENTS AND METHODS: In a total of 207 patients with nodular thyroid disease who underwent to thyroidectomy, we retrospectively compared: a) cytological and histological results, b) presence of anti-thyroid autoantibodies (ATA), tissue hypoecogenicity at ultrasound esamination (USH) and lymphocytic thyroid infiltration (LTI), as parameters of thyroid autoimmunity. Cytology were classified in three classes of increased risk of malignancy: benign (class II); mild increased risk (class III) and suspect or malignant (class IV) nodules. Histological diagnoses were: follicular adenoma (FA), follicular carcinoma (FC) and PTC. RESULTS: As displayed in the Table, when presence/absence of thyroid autoimmune parameters were considered, a significantly increased prevalence of class IV cytology and PTC in ATA+ nodules were found. A significantly increase prevalence of PTC and an high parevalence of class IV cytology was also observed in thyroid nodules associated to LTI. These results were also confirmed when the highest ATA titres and diffuse LTI were considered. Although USH correlated with the presence of ATA and LTI, no association between USH, cytological and histological results was found. Our study confirmed a significant association between PTC and thyroid autoimmunity, in particular with ATA postivity and diffuse LTI. The analysis of ATA titres and LTI pattern provide evidence that this relationship may be considered as a true association instead a secondary autoimmune reaction.