Multinodular goiter: A study of malignancy risk in nondominant nodules

The long-standing belief that multinodular goiters are associated with a lower risk of developing into carcinoma has been challenged by the results of some recent studies. In addition, we have noticed in our practice that a sizable proportion of cancers have been arising from nondominant nodules. We performed a retrospective study of 223 cases to determine (1) the incidence of carcinoma in multinodular goiters that required surgical management in our local, predominantly Asian population and (2) the incidence of carcinoma arising from nondominant nodules. We reviewed the records of all patients with a multinodular goiter who had undergone a thyroidectomy over a period of more than 10 years in our Department of Otolaryngology-Head and Neck Surgery. We examined the histopathology reports for (1) the presence of carcinoma, (2) whether the carcinoma was isolated/unifocal or multifocal, (3) the histologic type of cancer, and (4) whether the isolated/unifocal cancers arose from the dominant or nondominant nodule. Our study population was made up of 47 males and 176 females, aged 15 to 90 years (mean: 53). We found that the incidence of malignancy in surgically treated multinodular goiters was 14.3% (32 of 223 patients). Of the 32 malignancies, 18 (56.3%) were isolated/unifocal and 14 (43.8%) were multifocal. In the isolated/unifocal group, 9 malignancies (50.0%) arose from nondominant nodules and 8 (44.4%) from dominant nodules; in the remaining case, the nodule of origin could not be determined. Our findings corroborate those in the recent literature in that the risk of malignancy associated with multinodular goiters is comparable to that of single thyroid nodules. We recommend that physicians be equally vigilant when monitoring dominant and nondominant nodules.