Microscopic papillary thyroid cancer as an incidental finding in patients treated surgically for presumably benign thyroid disease.

Background: Papillary thyroid microcarcinoma (PTMC) is a relatively common entity in the general population.

Aim: To present our experience with papillary thyroid microcarcinoma of the thyroid as an incidental finding in patients treated surgically for presumably benign thyroid disease.

Settings And Design: Histology reports of patients treated surgically with a preoperative diagnosis of benign thyroid disease were reviewed to identify patients with PTMC. Patients with a preoperative diagnosis of thyroid cancer were excluded from this study.

Materials And Methods: The files of 380 patients who underwent surgery for presumably benign thyroid disease in our hospital from 1990 to 2002 were reviewed. Data regarding patient's demographics, pathology findings, management and outcomes, were retrieved.

Statistical Analysis Used: The findings are expressed as absolute numbers and as percentages (with reference to the total number of patients of this study).

Results: Twenty-seven patients with PTMC diagnosed incidentally following thyroid surgery for presumably benign thyroid disease (27/380 or 7.1%) (multinodular goiter = 20 patients, follicular adenoma = 6 patients, diffuse hyperplasia of the thyroid = 1 patient) are presented. Mean diameter of PTMC was 4.4 mm. In 11 patients (40.7%) the tumor was multifocal and in about half of them tumor foci were found in both thyroid lobes. In two patients the tumor infiltrated the thyroid capsule. Total/near-total thyroidectomy was performed in all these patients (in three as completion thyroidectomy). All patients received suppression therapy and 20 of them underwent adjuvant radioiodine therapy. Follow-up (mean 4.56 years, range 1-12 years) was completed in 25 patients; all these patients were alive and disease-free.

Conclusions: PTMC is not an uncommon incidental finding after surgery for presumably benign thyroid disease (7.1% in our series). The possibility of an underlying PTMC should be taken into account in the management of patients with nodular thyroid disease; total/near total thyroidectomy should be considered, at least in selected patients with presumably benign nodular thyroid disease.