Incidental thyroid papillary microcarcinoma on 1777 surgically treated patients for benign thyroid disease A monoinstitutional experience and literature review

Background We evaluated the frequency of incidental papillary thyroid microcarcinomas (mPTC) in thyroidectomies performed for benign diseases, to better characterize this nosologic entity and to assess the best treatment. Methods Between 2009 and 2017, a total of 1777 patients underwent surgery for benign thyroid disease. Patients with preoperative undetermined or positive for malignancy cytology were excluded, as well as incidental thyroid cancer larger than 1& x202f;cm. Results Total thyroidectomy was performed in 1649 patients (92.7%) and hemithyroidectomy in 128 (7.2%). Papillary thyroid cancer, sized between 2-10& x202f;mm, was found in 89 patients (5%), which were all by definition microcarcinomas (mPTC). In 11 patients mPTCs were multifocal and in 7 bilateral. Just 6 patients received hemithyroidectomy and later underwent radical surgery without complications. No tumor-related morbidity or mortality was observed. The chi(2) test showed a statistically significant association between mPTC and non-toxic multinodular goiter. Discussion In the literature, the rates of incidental mPTC vary, due to various factors such as histopathological examination and sampling numbers. Regarding surgical treatment, some authors support a "conservative" approach for the positive prognosis, but considering that it can be associated with mortality, lymph node recurrence and metastasis, its treatment is still controversial. Conclusions Our experience confirms that total thyroidectomy in multinodular goiter is a safe procedure, which ensures endocrine control and oncologic complete tumor resection, in case of mPTC. In uninodular goiter, we recommend hemithyroidectomy; if mPTC is discovered, we suggest radical surgery especially in patients older than 50 years and with familial disposition for thyroid cancer and peripheral tumors larger than 5& x202f;mm and aggressive variants.