Ultrasonographic evaluation of thyroid nodules: comparison of ultrasonographic, cytological, and histopathological findings

Abstract

Thyroid ultrasonography (US) and fine needle aspiration biopsy (FNAB) are the most important tools in evaluating thyroid nodules. A total of 3,404 nodules in 2,082 cases referred to our clinic between 2005 and 2008 were analyzed retrospectively. Considering US features of nodules, risk factors predicting malignancy were: margin irregularity as the most important predictor, hypoechoic pattern and microcalcification (Odds ratios: 63.2, 13.3, 7.03, respectively). Cytologic results of the patients were as follows: 1,718 (82.5%) benign, 196 (9.4%) suspicious, 68 (3.3%) nondiagnostic, and 100 (4.8%) malignant. In histopathologic examination, we determined a malignancy rate of 7.59% (158/2082). We calculated the sensitivity of FNAB as 89.16%, specificity as 98.77%, positive predictive value as 96.10%, negative predictive value as 96.39%, and accuracy as 96.32%. In cytologic examination, the malignancy rate of subcentimetric (≤1 cm) nodules was higher than supracentimetric (>1 cm) nodules (5.1% vs. 1.5%, P = 0.001). In postoperative histopathologic examination, although the malignancy rate of subcentimetric nodules was higher than that of supracentimetric nodules, the difference was statistically insignificant (5.5%, 4.4%, respectively; P > 0.05). Cytologically diagnosed malignancy was detected in 4.5% of patients with multiple nodules, while it was present in 6% of patients with solitary nodule indicating no significant difference. However, postoperative histopathologic examination revealed a significantly higher malignancy rate in patients with solitary nodule compared to in patients with multiple nodules (11.7%, 6.5%; respectively, P < 0.001). The malignancy rate of patients operated for suspicious cytology was found to be 46.15%; for nondiagnostic cytology, it was 64.29%. In conclusion, ultrasonographically, hypoechoic pattern, microcalcification and margin irregularity of thyroid nodules are important features in determining the malignancy risk. The nodule size alone still remains inadequate to exclude malignancy risk.

DIAGNOSIS IN ENDOCRINOLOGY: Quantification of cancer risk of each clinical and ultrasonographic suspicious feature of thyroid nodules: a systematic review and meta-analysis

“…Of these, 235 studies were retrieved for further investigation, and 41 studies (14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54) met the final selection criteria and were included in the analysis. All 41 studies were observational studies published in peer-reviewed journals between 1989 and 2012.…”

Evaluation of cytopathological findings in thyroid nodules with macrocalcification: macrocalcification is not innocent as it seems

“…Morphological features of nodules such as echogenicity, texture, margin regularity, presence of halo, presence and type of calcification can be assessed by high resolution US. Margin irregularity, hypoechogenicity and microcalcification were considered to be important risk factors for malignancy, however, size of thyroid nodule alone was not considered as a risk factor (6).…”

Pre-operative diagnosis of thyroid cancer: Clinical, radiological and pathological correlation

“…FNA accuracy is reported to range between is 80 -90% 13 though the methodology for generating these predictive values vary from series to series. False negative benign results are reported to be between 1-3% in a number of research studies 21,22,25,31 . In contrast to these high accuracy rates, FNA results in our series were unhelpful in 53% of patients.…”

“…The vast majority of thyroid nodules are in women and historically nodules in men were believed to have a higher risk of malignancy. Even though recent international guidelines still include this risk factor, U n i v e r s i t y o f C a p e T o w n 11 many recent studies do not support the finding 21,22,23 . Some even demonstrate a higher incidence in women than men 24 .…”