Incidence and morphological features of thyroid papillary microcarcinoma in Graves’ disease

Abstract

Introduction/Objective. Association of Graves’ disease (GD) and thyroid cancer is reported in a wide range from 0% to 33.7%. Papillary thyroid carcinoma (PTC) is the most commonly diagnosed malignancy in GD, namely its variant – papillary thyroid microcarcinoma (PTMC). The increasingly frequent PTMC disclose favorable biological behavior with low mortality and recurrence rates. The aim of this work is to report our experience on the frequency and morphological features of PTMC in surgically treated patients with GD. Methods. Over a period of three years, total or near-total thyroidectomy was performed in 129 patients with GD. Results. Incidental PTMC was diagnosed in 24 (18.7%) patients with GD. The mean tumor diameter was 3.03 ± 2.17 mm. The average age of patients in the GD with PTMC group was 48.50 ± 13.07 years, while in the GD without PTMC group it was 41 ± 13.12 years, and it proved to be statistically significant ( p = 0.045). Most of the PTMC were unifocal (83%), and the most common morphological features of PTMC were intraparenchymal localization (62.5%), follicular morphology (66.7%), and infiltrative growth pattern (62.5%). Extrathyroidal extension, lymphatic invasion and multifocality of PTMC were more commonly related with subcapsular localized PTMC. The presence of at least one nodule in the GD with PTMC group was 58.3%, while in the GD without PTMC group it was 26.7%, and it was statistically significant (p = 0.003). Conclusion. Our results showed a high incidence of PTMC (18.7%) in patients with GD. Clinically, the most important morphological characteristics of PTMC were related with its subcapsular localization.

Keywords

• Grave's disease
• thyroid papillary microcarcinoma
• morphology