Follow-up evaluation and clinical course of patients with benign nodular thyroid disease

Reliance on fine-needle aspiration biopsy (FNAB) in determining which patie nts with a thyroid nodule can be observed depends on a low false-negative r ate. The purpose of this study was to determine the false-negative rate of FNAB, the utility of routine repeat FNAB, and the clinical course of patien ts with benign nodular thyroid disease. The records of all patients with no dular thyroid disease evaluated between June 1990 and May 1998 were reviewe d. Patients with a benign FNAB were identified, and nodule size, subgternal extension, the results of repeat FNAB, clinical course, histologic diagnos is, and length of follow-up were determined. Of the 341 patients referred w ith nodular thyroid disease, 121 had a benign FNAB. In 80 patients with a m ean nodule size of 3.5 +/- 1.6 cm, clinical follow-up was recommended. The mean duration of follow-up was 20.5 months for 74 patients, and 6 patients were lost to follow-up. Nodule resolution was observed in 7 patients. Repea t FNAB was performed in 45 patients and was benign in 39 (87%), nondiagnost ic in 2 (4%), cellular in 3 (7%), and malignant in 1 (2%). Thyroidectomy wa s performed in the patients with the cellular and malignant aspirates, and the pathology was adenomatous hyperplasia (2), follicular adenoma (1), and papillary carcinoma (1). Thyroidectomy was performed for increasing nodule size and/or compressive symptoms in 41 patients with a mean nodule size of 5.7 +/- 1.9 cm, 19 of whom had substernal extension (P < 0.05). Pathology i ncluded benign disease in 39, papillary cancer in 1, and lymphoma arising i n Hashimoto's thyroiditis in I patient. Given that repeat FNAB was of value in only 1 patient and the false-negative rate for FNAB was only 2.5 per ce nt, the routine use of repeat FNAB in patients with benign nodular thyroid disease may not be justified. Development of compressive symptoms and diagn osis of unsuspected malignancy in patients with nodule enlargement, includi ng lymphoma in patients with Hashimoto's thyroiditis, underscores the impor tance of long-term follow-up.