Follow-Up Evaluation and Clinical Course of Patients with Benign Nodular Thyroid Disease

Abstract

Reliance on fine-needle aspiration biopsy (FNAB) in determining which patients with a thyroid nodule can be observed depends on a low false-negative rate. 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 patients with benign nodular thyroid disease. The records of all patients with nodular thyroid disease evaluated between June 1990 and May 1998 were reviewed. Patients with a benign FNAB were identified, and nodule size, substernal extension, the results of repeat FNAB, clinical course, histologic diagnosis, and length of follow-up were determined. Of the 341 patients referred with nodular thyroid disease, 121 had a benign FNAB. In 80 patients with a mean 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. Repeat FNAB was performed in 45 patients and was benign in 39 (87%), nondiagnostic in 2 (4%), cellular in 3 (7%), and malignant in 1 (2%). Thyroidectomy was 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 included benign disease in 39, papillary cancer in 1, and lymphoma arising in Hashimoto's thyroiditis in 1 patient. Given that repeat FNAB was of value in only 1 patient and the false-negative rate for FNAB was only 2.5 per cent, the routine use of repeat FNAB in patients with benign nodular thyroid disease may not be justified. Development of compressive symptoms and diagnosis of unsuspected malignancy in patients with nodule enlargement, including lymphoma in patients with Hashimoto's thyroiditis, underscores the importance of long-term follow-up.