Fine-needle aspiration cytology of the thyroid gland: puzzling points regarding palpable and nonpalpable nodules

ABSTRACT

The aim of the present study was to evaluate whether fine-needle aspiration cytology (FNAC) is a useful method for the investigation, in out patients, of both palpable and nonpalpable thyroid nodules. A total of 299 FNAC thyroid punctures performed in 147 palpable and 152 nonpalpable lesions (ultrasound-guided) between 1996 and 1998 were compared. FNAC of palpable lesions was performed at the Outpatient Clinic of São Paulo Hospital, Federal University of São Paulo - UNIFESP and nonpalpable cases were submitted to ultrasound-guided fine-needle aspiration at São Caetano Beneficiente Hospital. Both series were examined during the same period from April 1997 to May 1998. Guided puncture (nonpalpable nodules) showed the following results: 50 percent goiter and nodular goiter; 17.10 percent cellular follicular lesions; 15.10 percent lymphocytic thyroiditis; 2.63 percent papillary carcinoma; 1.97 percent follicular and Hürthle cell neoplásias; and 13,15 percent unsatisfactory samples. Palpable nodules showed the following results: 54.42 percent nodular goiter; 17 percent follicular cell lesions; 10.2 percent lymphocytic thyroiditis; 4.76 percent papillary carcinoma; 4.08 percent Hürthle and follicular neoplasia, 0.68 percent anaplastic carcinoma, and 8.84 percent unsatisfactory samples. Similar frequencies of the specific cytopathological diagnosis were observed for the two series of palpable and nonpalpabie lesions. The frequencies of malignant conditions were similar for the two series and to the frequencies reported in epidemiological studies.