RESUMO
AIM: The aim of this paper was to evaluate the diagnostic efficiency of cytology results obtained through fine-needle aspiration (FNA) in partially cystic thyroid nodules and to examine the association between specific ultrasonographic evidence and malignancy. METHODS: A descriptive, observational, cross-sectional study examining the relationship between cytological and ultrasonographic findings in a group of patients with partially cystic thyroid nodules. The following ultrasound characteristics were examined: 1) nodule size (in mm); 2) percentage of the solid portion of the nodule (greater or less than 50%); 3) echogenicity of the solid portion (hypoechoic, isoechoic, or hyperechoic); 4) eccentricity of the solid portion; 5) regularity of the margins, and 6) presence or absence of microcalcifications. RESULTS: The ultrasound (US) and cytological characteristics of the partially cystic thyroid nodules of 145 patients, 127 women with a mean age of 53.1 years (SD 19.7) and 18 men with a mean age of 60 (SD 19.7), were reviewed. The mean size of the nodules was 28.07 mm (SD 11.23). Thirty-seven (25.5%) were solitary nodules and 98 (72.59%) formed parts of multinodular goiters. Twenty-eight (19.3%) of the cytologies proved to be inadequate samples, 104 (71.7%) were benign, 7 (4.8%) were suspicious, and 4 (2.8%) were malignant. The sensitivity for detecting malignancy was >90% when the percentage of the solid portion of the nodule was greater than 50%; these values remained unchanged when combined with other sonographic findings. The greatest specificity for malignancy was associated with the presence of microcalcifications (99%); however, none of the associations observed were statistically significant. CONCLUSION: FNA cytology is an essential diagnostic tool in both partially cystic and solid nodules. Examination of several individual ultrasound characteristics of these nodules, such as the percentage of the solid component, as well as other common characteristics, including the echogenicity or the presence of microcalcifications, may greatly facilitate the diagnostic process.
