Preoperatively Undiagnosed Thyroid Cancer in Patients Undergoing Surgery for Benign Multinodular Goiter

Multinodular goiter (MNG) is the most common systemic endocrine disease, with a gender ratio (women to men) of 3:1. Incidental thyroid malignancy, preoperatively diagnosed as benign tumor, is a common problem after thyroid surgery. Therefore, the present study was conducted to investigate the role of total thyroidectomy in the diagnosis of types of thyroid cancer after surgery, preoperatively diagnosed as multinodular goiter, and to determine the risk factors of thyroid malignancy in multinodular goiter.

This prospective study was conducted on 120 patients who were divided into malignant and benign groups based on thyroid tumor diagnosis. All patients underwent total thyroidectomy under general anesthesia. Patients were selected based on complete history, clinical examination, laboratory and radiological findings, as well as ultrasound-guided FNA and ultrasound machine used to confirm the diagnosis of thyroid cancer and lymph node metastasis.

Among the 120 selected patients, 20 patients were excluded and the remaining 100 patients were divided into two groups: 13% malignant and 87% non-malignant group, which were involved in nodular hyperplasia, inflammatory and benign tumors. The median age for the malignant group (40 years) was higher than the non-malignant group (30 years). Thyroid carcinoma was diagnosed in 46.2% of men and 53.8% of women (p=0.045). In addition, male gender compared to female gender has 2.7 times the analysis as a risk factor for thyroid cancer (relative risk=2.714).

According to the results of this study, total thyroidectomy in patients with multinodular goiter lowers the risk of reoperation because of the presence of hidden malignancy in this benign disease (MNG). Male gender is an important risk factor for thyroid cancer and age factor has no significant association with thyroid cancer post-operatively. Ultrasonography-guided FNA, ultrasound machine, and clinical examinations are not enough for final diagnosis of thyroid cancer preoperatively.