Hashimoto’s thyroiditis and thyroid cancer: results of a echographic, cytological and histological study.

S. Mariotti;B. Marziani;V. Matta;G. Baghino;M. L. Lai;L. Minerba;F. Boi

2007-01-01

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Abstract

Objective: The association between lymphocytic thyroiditis or Hashimoto’s thyroiditis (HT) and papillary thyroid carcinoma (PTC) has been suggested by pathological studies, but it is difficult to prove due to the contrasting results obtained with different methodological approaches. Aim of this study was to evaluate this association comparing several diagnostic parameters. Patients and Methods: In a total of 207 patients thyroidectomized for thyroid nodules, we retrospectively compared: a) cytology and histology, b) presence of anti-thyroid autoantibodies (ATA), thyroid hypoecogenicity at ultrasound examination (USH) and lymphocytic thyroid infiltration (LTI), as parameters of HT. Cytology were classified as: benign (class II); mild increased risk (class III) and suspect or malignant (class IV) nodules. Histology were indicated as: follicular adenoma (FA), follicular carcinoma (FC) and PTC. Results: When presence/absence of HT parameters were considered, a significantly increased prevalence of class IV vs class II and III cytology (51.2% vs 35%) and PTC vs FA (44.5% vs 26.7%) in ATA positive nodules were found (p<0.05). A significantly increased prevalence of PTC vs FA (54.8% vs 35.6%, p<0.05) and an high prevalence of class IV vs class II and III cytology (57% vs 44.6%) were also observed in LTI positive nodules. These results were also confirmed with the highest ATA titres and diffuse LTI pattern were considered. Although the presence of USH correlated with ATA and LTI positivity, no association between USH and cytological and histological results were found. Conclusions: Our study confirmed a significant association between PTC and TH, in particular with ATA and LTI positivity, providing evidence for a true association instead a secondary autoimmune reaction to PTC.