Higher incidence of tall cell variant of papillary thyroid carcinoma in Graves' Disease.

BACKGROUND

Patients with Graves' disease (GD) and thyroid nodules have an elevated risk of developing thyroid carcinomas, which is primarily accounted for by well-differentiated tumors. Among these tumors, certain histological variants, such as the diffuse sclerosing and tall cell carcinoma, are characterized by a more aggressive behavior. The aim of this study was to evaluate the incidence, the clinical behavior in relation to histological variants, and the outcome of papillary thyroid carcinoma (PTC) in a cohort of patients with GD who had undergone thyroidectomy.

METHODS

A total of 2188 patients who underwent total thyroidectomy participated in this retrospective, nonrandomized, population-based study at a General Hospital. Of these patients, 181 had GD. The parameters examined included the clinical characteristics of the tumor and the final pathological examination of the thyroid carcinoma.

RESULTS

PTC was diagnosed in 570 patients. Among the 61 with PTC GD-positive, 59.0% presented with the pure papillary variant, 19.7% with the follicular variant, 6.6% with the sclerosing variant, and 18.0% with the tall cell variant (TCV) of PTC. Among 509 PTC GD-negative, 80.6% had pure papillary variant, 9.0% follicular variant, 3.7% sclerosing variant, and 6.1% TCV. Patients with tumor size >5 and ≤10 mm demonstrated that lymph node metastasis (p=0.001) and TCV in histological examination (p=0.003) were statistically significantly associated with GD-positive PTC.

CONCLUSIONS

The incidence of PTC in GD-positive patients is higher than that in GD-negative patients. Aggressive variants of PTC, such as the TCV, were more frequent in nodular micro-PTC. These findings suggest that prompt and meticulous evaluation of nodules in any patient with GD associated with nodular alterations must be considered.