Fine needle aspiration biopsy (FNAB) performed for diffuse and nodular goiter in the past 5 years, was evaluated in 1399 cases. Surgery was performed on the basis of FNAB cytologic diagnosis that was positive or suggestive of malignancy and/or a suggestive clinical history. Surgery also was performed in cases of cold nodules with negative FNAB results that did not respond to 6 months of suppressive thyroxine therapy. A correlation of cytologic findings with histologic findings was possible in 415 patients who underwent surgery: the evaluation of FNAB results yielded better results when suspicious cytologic findings were considered to be positive (2.4% false-negative, 86.3% sensitivity) rather than negative (6.5% and 65.78, respectively). FNAB has become a useful procedure in the study and diagnosis of thyroid diseases. It is a simple, rapid diagnostic procedure that may be used to expedite the management ofmalignant lesions.Cancer 59:1206-1209, 1987. INE NEEDLE ASPIRATION BIOPSY (FNAB) has beenF introduced in our hospital in the past 5 years as a routine procedure for the study of thyroid disease. In some centers, FNAB is a safe and inexpensive tool in the study of thyroid nodules, although it is not yet widely used, partly because it requires the services of an expert cyto-The majority of reports on the technique refer to nodular goiter, using FNAB to distinguish benign from malignant lesions pre~peratively,*-~ although thyroid nodules only represent about 20% of thyroidopathies.6 We have undertaken a study to evaluate the usefulness of FNAB as a complement to clinical, hormonal, gammagraphic, and ultrasonographic studies in both diffuse and nodular goiters. The authors thank Prof. F. Martinez Tello, Head of the Pathology Department at our hospital, for his kindly assistance and advice in the preparation of this manuscript. Material and Methods FNABAccepted for publication October 27, 1986. ular goiters, with or without clinical symptomatology. Patients were not selected for this study, but their specific consent was required. Age ranged from 9 to 84 years (mean, 43 years); 10.5% of the patients were male and 89.5% were female. FNAB was always made after clinical and biochemical (thyroid hormones and antibodies) studies, 9 9 m T~ imaging, and ultrasonography. According to these tests, 261 cases were diffuse goiters, 281 were multinodular goiters, 83 5 were solitary thyroid nodules, and 22 were miscellaneous. A correlation was established between cytologic findings (FNAB) and postoperative pathologic results in 415 patients. Surgery was performed on subjects with positive or suspicious FNAB cytologic diagnoses and/or suggestive clinical histories, and in patients with cold thyroid nodules and negative FNAB results that did not respond to 6 months of suppressive thyroxine therapy.The procedure was similar to that described by Lowhagen et ~1 .~ Using a Cameco syringe pistol (Cameco AB, Taby, Sweden) with 0.6 to 0.8 mm gauge needles that were 20 mm in length. Local anesthetic was not used, and at least two puncture...