Occult thyroid carcinoma in our experience -- should we reconsider total thyroidectomy for benign thyroid pathology?

BACKGROUND The reported incidence rate of occult thyroid carcinoma in patients operated for benign thyroid pathology has been much higher than expected in the last years,especially for multinodular goitre, which raises the question about which should the proper surgical management for these cases be. AIM To assess the incidence rate of OTC in a single medium volume surgical center and to establish the correct indication for initial surgical management, as well as to identify the benign thyroid pathology most frequently associated with OTC. We also reviewed the relevant scientific literature on this topic. MATERIAL AND METHOD We conducted a retrospective study in the General Surgery Clinic of "Prof. dr. Agrippa Ionescu" Clinical Emergency Hospital, Bucharest, on a series of 145 patients who underwent surgical interventions for preoperatively diagnosed benign thyroid pathology over a ten year period, between 1st January 2002 - 31st December 2012. All cases of known thyroid cancer were excluded. RESULTS Incidence rate of occult thyroid carcinoma in our series was 6.9 % (10 out of 145 patients), 80 % of them being diagnosed with multinodular goitre and two cases (20 %) with Hashimoto's lymphocytic thyroiditis. 6.8 % of all patients with multinodular goitre were found to present occult carcinoma,but this association was without statistical significance(p 0.05). Incidence rate of occult cancer among patients with Hashimoto thyroiditis was proved to be as high as 28.6%,statistically significant (p=0.020). The mean size of postoperatively diagnosed occult microcarcinoma was 7 mm, ranging between 3 mm and 14 mm, 90% of them being smaller than 1cm. Histologically, papillary microcarcinoma was found in all cases. The mean age of the patients diagnosed with occult microcarcinoma was 47.8 years with majority of the female gender. The most frequent operation performed was total thyroidectomy (70.8%). Overall morbidity in our series was 6.9% with a 0.7 % mortality rate (1 case). CONCLUSIONS In our opinion, primary total thyroidectomy should be performed as the procedure of choice for the most part of preoperatively diagnosed benign thyroid pathology and particularly for multinodular goitre and Hashimoto thyroiditis,in order to radically resect all possible foci of aggressive thyroid microcarcinomas.Abbreviations and Acronyms: OTC (Occult Thyroid Carcinoma), PTMC (Papillary Thyroid Microcarcinoma); TT(Total Thyroidectomy), MNG (Multinodular Goitre), GD(Graves' disease), TNG (Toxic Nodular Goitre), FNAB(fine-needle aspiration biopsy).