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The possible association between Hashimoto's thyroiditis (HT) and papillary thyroid carcinoma (PTC) is a still debated issue. We analyzed the frequency of PTC, TSH levels and thyroid autoantibodies (TAb) in 13 738 patients (9824 untreated and 3914 under L-thyroxine, L-T4). Patients with nodular-HT (n=1593) had high titer of TAb and/or hypothyroidism. Patients with nodular goiter (NG) were subdivided in TAbKNG (n=8812) with undetectable TAb and TAbCNG (n=3395) with positive TAb. Among untreated patients, those with nodular-HT showed higher frequency of PTC (9.4%) compared with both TAbKNG (6.4%; P=0.002) and TAbCNG (6.5%; P=0.009) and presented also higher serum TSH (median 1.30 vs 0.71 &mgr;U/ml, P<0.001 and 0.70 &mgr;U/ml, P<0.001 respectively). Independently of clinical diagnosis, patients with high titer of TAb showed a higher frequency of PTC (9.3%) compared to patients with low titer (6.8%, P!0.001) or negative TAb (6.3%, P<0.001) and presented also higher serum TSH (median 1.16 vs 0.75 &mgr;U/ml, P<0.001 and 0.72 &mgr;U/ml, P<0.001 respectively). PTC frequency was strongly related with serum TSH (odds ratio (OR)=1.111), slightly related with anti-thyroglobulin antibodies (OR=1.001), and unrelated with anti-thyroperoxidase antibodies. In the L-T4-treated group, when only patients with serum TSH levels below the median value (0.90 &mgr;U/ml) were considered, no significant difference in PTC frequency was found between nodular-HT, TAbKNG and TAbCNG. In conclusion, the frequency of PTC is significantly higher in nodular-HT than in NG and is associated with increased levels of serum TSH. Treatment with L-T4 reduces TSH levels and decreases the occurrence of clinically detectable PTC. [ABSTRACT FROM AUTHOR]

Background The relationship between thyroid autoimmunity and cancer is still uncertain. Patients We approached this issue in 570 consecutive patients submitted to thyroidectomy for an indeterminate nodule on cytology. Thyroid autoimmunity was defined as positivity of circulating thyroid autoantibodies (TAb), autoimmune hypo- or hyperthyroidism, thyroid hypoechogenicity on ultrasound, and lymphocytic infiltration on histology. Results TAb were found in 122/570 (21·4%), hypoechogenicity in 115/570 (20·1%), and lymphocytic infiltration in 117/570 (20·5%) of patients. The three features of thyroid autoimmunity were highly concordant: hypoechogenicity was observed in 71/448 (15·8%) patients with negative TAb and in 44/122 (36%) with positive TAb ( P < 0·0001); lymphocytic infiltration was found in 53/448 (11·8%) patients with negative TAb and in 64/122 (52·4%) with positive TAb ( P < 0·0001); hypoechogenicity on ultrasound was observed in 73/453 (16·1%) patients without, and in 42/117 (35·9%) with lymphocytic infiltration ( P < 0·0001). None of these parameters was associated with malignancy. TAb were found in 32/135 (23·7%) patients with carcinoma and in 90/435 (20·6%) with a benign lesion ( P = NS); hypoechogenicity was observed in 26/135 (19·2%) patients with carcinoma and in 89/435 (20·4%) patients with benign lesions ( P = NS); lymphocytic infiltration was present in 28/135 (20·7%) patients with carcinoma and in 89/435 (20·4%) with benign lesions ( P = NS). The frequency of cancer in 11 patients with clinically overt thyroid autoimmune disease did not differ from that observed in the whole study group. Conclusion In this group of patients with indeterminate thyroid nodules at cytology, clinical and pathological criteria of thyroid autoimmunity were strongly concordant and not associated with malignancy. [ABSTRACT FROM AUTHOR]

Objective The cytological patterns of follicular and Hϋrthle cell nodules are included among the indeterminate results of fine-needle aspiration cytology, because distinction between benign and malignant lesion can only be made on histological criteria. The diagnostic value of atypia at cytology, clinical parameters and echographic patterns were examined to establish the risk of malignancy in 505 patients with follicular and Hϋrthle cell thyroid nodules at cytology. Design and patients The study included 505 consecutive patients who had undergone thyroidectomy from the period 2002–2005. Results Histological diagnosis of malignancy was carried out in 125 of 505 (25%) patients, the follicular variant of papillary carcinoma being the most frequent histotype. Only atypia at cytology ( P < 0·0001) and spot microcalcifications at ultrasound ( P = 0·009) were predictive of malignancy. Male gender, normal thyroid volume, single nodularity, nodule hypoechogenicity, size and blurred margins were associated with malignancy, although not significantly. An arbitrary clinical score allowed the identification of patients with high (41%, 110 patients) and low (16%, 242 patients) risk of malignancy. Combining the clinical score with the presence of atypia at cytology we could identify 30 patients (6%) in whom the risk of malignancy was as high as 63%. Conclusions Twenty-five per cent of patients with a cytological result of follicular and Hϋrthle cell thyroid lesion had a final diagnosis of malignancy. Only atypia at cytology and spot microcalcifications at thyroid ultrasound were significantly associated with malignancy. Other clinical parameters and thyroid ultrasound patterns can be used to set up a clinical score useful for predicting the individual risk of malignancy before surgery. [ABSTRACT FROM AUTHOR]