Thyroid nodules indeterminate by needle biopsy.

In our experience with 121 patients 18 (15 percent) thyroid nodules studied by needle biopsy were considered indeterminate relative to the presence of a low-grade, well-differentiated carcinoma. For 11 of the 18 patients, operation was performed with carcinoma identified in two (18 percent). Although experience reduced this problem, the frequency of carcinoma justifies operation for patients with indeterminate thyroid nodules by needle biopsy, unless other factors dictate otherwise. Inadequate results of fine-needle aspiration biopsy requires a determination of therapy on the basis of other clinical factors. However, permanent disappearance or great reduction in size following aspiration of cystic nodules, repeat biopsy, and biopsy with large needles are important in supporting nonoperative therapy. The indeterminate and inadequate cases must be considered in assessing reports of the use of needle biopsy of thyroid nodules. The large size of a thyroid nodule and previous external radiation therapy are factors supporting operative treatment. Improved selection of patients with benign thyroid nodules for thyroid hormone suppression therapy is needed--thyroid-releasing hormone testing may be of help.