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.