Incidentally vs non-incidentally diagnosed papillary thyroid carcinoma: are there differences?

Graphical abstract Abstract Background Thyroid carcinoma (TC) incidence increased over the past 50 years. The explanation for this is not consensual. Objective Compare incidental vs non-incidental TC (ITC vs NITC) regarding demographic, clinical, histological data and 5-year clinical outcomes. Design Retrospective analysis of 225 papillary TC (PTC) cases that completed a 5-year follow-up. Methods Created 2 groups: ITC (including the incidentalomas) and NITC (cases of palpable or visible nodules or with thyroid compressive complaints). Results Included 225 PTC (122 were ITC). There were 95 women in ITC and 78 in NITC. ITC patients were significantly older (53.3 ± 14.8 vs 47.2 ± 17.7, P = 0.006). Groups had no differences in family history of TC. ITC mean tumour size was smaller (19.1 ± 9.2 vs 28.6 ± 16.2, P 20 mm comprised 36.1% of ITC and 58.2% of NITC. We found no differences in tumour multifocality, histological thyroiditis, aggressive PTC subtypes, capsule or lymph-vascular invasion and gross extrathyroidal extension. There were no differences regarding the number of patients submitted to RAI or in RAI activity. pTMN staging showed higher prevalence of T3a and T4 cases ( P 20 mm. As even large tumours can be ITC, overdiagnosis is the most likely cause of increasing incidence of TC.