Endocrine Abstracts

Introduction: Incidental papillary thyroid carcinoma (PTC) in patients undergoing thyroidectomy for benign multinodular disease is a well-recognised finding. Its true prevalence remains uncertain and shows great variability between studies, ranging from 7–25%. Our purpose was to review the prevalence of PTC in thyroid glands removed for benign nodular disease at a Northern Portuguese tertiary hospital.

Methods: From December 2012 to December 2014, the histological reports of patients treated surgically for benign nodular thyroid disease were reviewed. We excluded patients with thyroid hyperfunction and those with any suspicious cytological findings (Bethesda category ≧III). Data regarding demographics and pathological findings were retrieved.

Results: patients were included in the analysis, with a mean age of 55±15 years; 87% were females. The overall prevalence of malignancy (PTC) found was 15.8% (95% CI, 11.4–21.5%). There were no statistically differences between PTC and benign groups regarding patient’s age and gender. The pathological tumour size ranged between 1 and 55 mm (median 8 mm). Most cases of PTC were microcarcinomas (19 in 32, 59.4%), with a median diameter of 4 mm (range, 1–9 mm). In respect to macrocarcinomas (13 in 32, 40.6%), the median tumour diameter was 35 mm (range, 11–55 mm). In seven patients (22%), the tumour was multifocal and in one patient (3%) vascular invasion was documented. The most common variants of PTC found were classical and follicular with 59.4 and 37.5% respectively.

Conclusions: In our series, microscopic PTC prevalence in patients undergoing thyroid surgery for benign euthyroid disease seems to be similar to the previously described. These high rates of pathological incidental thyroid carcinomas should be taken into account and drive appropriate diagnostic and therapeutic approaches.