Abstract
The incidence of functioning thyroid nodules is considered to be low in Japan. However, we perform 123I scintiscan in most cases of thyroid tumors and when thyroid nodules are hot on scintiscan, we advise patients that thyroid nodules should be excised. In this study, we retrospectively reviewed the incidence, diagnostic and operative methods and pathologic characteristics of functioning thyroid nodules from 1991 to 1997 at Tenri Hospital.
Among 1177 cases of thyroid diseases in which scintiscans were performed, ninety-one cases (7.7%) had hot nodules and the incidence of functional thyroid nodules is higher than has been reported in Japan.
The incidence of euthyroid nodules was higher than expected among those clearly diagnosed as autonomously functioning thyroid nodules by triiodothyronin (T3) suppression test. This result and one false positive case of preoperative fine needle aspiration cytology showed the importance of 123I scintigrams as an initial diagnostic method of thyroid nodules.
Thyroid lobectomies or total thyroidectomies were performed in 48 cases. Papillary carcinomas coexisted in eleven cases (22.8%), and four functioning nodules themselves were papillary carcinomas. In consideration of this data and the difficulty of controlling hyperthyroidism due to functioning thyroid nodules, operations should be used as a primary treatment method, even though in our study, postoperative hypothyroidism occurred in ten cases (22.2%) in which thyroid lobectomy was performed.
