Incidental papillary thyroid microcarcinomas in thyroidectomy specimens: A single-center experience from Turkey

Papillary thyroid microcarcinoma (PTM) is a relatively common entity in the general population. PTM is often asymptomatic and is detected incidentally during the histopathological examination of thyroidectomy specimens from operations because of benign thyroid disease.

The aims of the study are to determine the incidence of incidental papillary thyroid microcarcinomas (IPTMs) in our center, to examine the clinicopathologic characteristics of these tumors, and to present our experiences.

This study includes 827 patients who underwent thyroidectomy operation in our center between January 2013 and June 2017 and were examined histopathologically in the Pathology Clinic. Patients' demographic characteristics, preoperative diagnoses, operative procedure, histopathological findings, and postoperative prognostic indexes are presented.

Of the 827 patients, 138 (16.6%) were diagnosed with a malignancy. Of these, 124 were papillary carcinoma, 5 were follicular carcinoma, 4 were lymphoma, 2 were medullary carcinoma, 2 were anaplastic carcinoma, and 1 was poorly differentiated carcinoma. The IPTM incidence rate was 8.01%; the multifocality and bilaterality rates were 23.3% and 13.3%, respectively. In 98.3% of IPTM cases, total thyroidectomies were performed, and in 1.7% of cases, subtotal thyroidectomy was performed followed by complementary thyroidectomy. No relapse or metastasis was detected in any of these cases. A careful histopathological examination of the thyroidectomy specimen is essential because IPTM is frequently skipped in fine needle aspiration cytology. We consider it best to perform total thyroidectomies because bilaterality and multifocality rates are high in IPTM. Long-term life expectancy in these tumors is quite good.