Multinodular goiter is the most common indication for thyroidectomy in endemic iodine-deficient regions. Preoperative evaluation for thyroid cancer by means of fine-needle aspiration biopsy is difficult in multinodular goiter owing to the presence of multiple nodules, and thyroid cancer is frequently an unexpected postoperative finding. The risk for malignancy was thought to be lower in multinodular goiter compared with solitary cold nodules. Recent studies, however, documented that this was not the case. The incidence of thyroid cancer showed no significant difference in solitary cold nodules and in cold nodules of multinodular goiter, and patients with thyroid cancer frequently presented with multinodular goiter.21,26- 27 Reoperation should be performed in patients with incidentally found thyroid cancer if the histological criteria mandate RAI ablation and there is a large volume of thyroid remnant. In the present study, of 9 patients scheduled for RAI ablation, tumor size was smaller than 1.5 cm in 7. Although these patients were considered to be at low risk according to MACIS (Metastasis, Age, Curative resection, Invasion, Size) classification, histological examination revealed multifocality, thyroid capsule invasion, or extrathyroidial spread. Low-risk patients have a favorable prognosis, but multifocality, thyroid capsule invasion, and extrathyroidial invasion were shown to adversely affect the prognosis.28- 31 Baudin et al31 analyzed the data of 281 patients with thyroid microcarcinoma (<1 cm) and documented that patients with more than 1 tumor focus had a significantly higher rate of recurrence compared with those with unifocal tumors, and multifocality significantly influenced the prevalence of RAI treatment. The RAI ablation was found to be an important factor in prolonging the disease-free interval and survival in patients with well-diffferentiated thyroid cancer, even low-risk patients.32 In Turkey, a considerable number of patients undergoing operation for thyroid cancer adher to the postoperative follow-up program; however, patient noncompliance still constitutes a major problem, and some patients undergoing surgery for thyroid cancer delay seeking medical help until the development of serious complications. We prefer to take unfavorable histological findings into account when deciding on RAI treatment, despite the low-risk score. The preferred TSH level is higher than 30 mIU/L for effective RAI ablation.33 Despite interfering with proper RAI ablation, remnant tissue may contain residual carcinoma in 11% to 53% of patients who undergo subtotal thyroidectomy with no difference in the frequency in high- and low-risk patients.17,34- 39 Thyroid cancer might be detected in approximately 10% of thyroidectomy specimens of recurrent goiter, although the preceding operations were performed for benign goiter.40 Menegaux et al40 documented that 20% of such patients had multifocal cancer, lymph node metastasis, or distant metastasis.