Microcarcinoma and incidental carcinoma of the thyroid in a clinical series: Clinical behaviour and surgical management

Objectives. Papillary thyroid microcarcinomas (PTM) have not yet an agreed clinical management. The Authors compared PTMs with papillary thyroid carcinoma of larger size (LPTC) and incidental and not-incidental carcinomas. Materials and Methods. Review of clinical data of 67 patients (54 women, 13 men) prospectively stored in a standardised way in an electronic patient record system. Results. There were 36 cases of microcarcinoma (53.7%). Differences were not significant between PTM and LPTC groups as to patients personal data, TNM and MACIS staging, nodal involvement (8.3% vs 19.3%) and multifocality (25% vs 38.7%) while capsular invasion was significantly higher in LPTC (25% vs 54.8%). Nineteen incidental tumors were detected at pathological examination and they were all microcarcinomas. They were smaller than the remaining 17 not-incidental microcarcinomas but showed a similar clinical behaviour. There were not cancer related deaths nor recurrences in the follow up period in any group. Conclusions. Despite the excellent prognosis of PTM, a subset of these tumours shows aggressive biological and clinical features, like nodal or capsular invasion and multifocality. Actually, with the exclusion of size, they do not show any relevant difference from differentiated thyroid carcinoma of larger size. Since predictive cytogenetic markers are still missing, their treatment should then be the same as for conventional thyroid cancers.