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Benign and malignant thyroid nodules cannot be distinguished by ultrasonography
The background of the study. Thyroid nodules are common, but few are cancers. This study was done to determine if benign and malignant thyroid nodules can be distinguished by the shape of the nodule or other characteristics, as determined by ultrasonography.
How the study was done. The ultrasound and biopsy characteristics of 7455 thyroid nodules in 5198 patients were evaluated. Among the nodules, 38 percent were <1 cm in diameter. The ultrasound scans were evaluated by two investigators, who determined the following characteristics of each nodule: anteroposterior and transverse (A/T) diameter, degree of echogenicity, presence of calcification, characteristics of nodule margin (blurred or well-defined), and nodule blood flow. The nodules were biopsied, and the results were reported as benign, suspicious for malignancy, malignant, or inadequate. All patients who had biopsies reported as suspicious or malignant underwent surgery.
The results of the study. Among the 7455 nodules, 6135 biopsies (82 percent) were adequate (4495 patients) and 1320 (18 percent) were inadequate (703 patients). Among the nodules that were successfully biopsied, the mean longest dimension was 16 mm; 35 percent were <1 cm (small) and 65 percent were 
1 cm (large). The biopsy was suspicious or malignant in 8 percent of the patients, and 6 percent proved to have cancer. Overall, 5 percent of the nodules that were successfully biopsied were cancers (3 percent of the small nodules and 6 percent of the large).
No single ultrasonographic feature reliably distinguished the nodules that were cancers from those that were benign. The combination of an A/T ratio 1 and any two of the following—low echogenicity, blurred nodule margins, and calcifications within the nodule—were reasonably good predictors of cancer.
The conclusions of the study. No single ultrasonographic finding reliably distinguishes thyroid cancers from benign thyroid nodules.
The original article. Cappelli C, Castellano M, Pirola I, Gandossi E, De Martino E, Cumetti D, Agosti B, Rosei EA. Thyroid nodule shape suggests malignancy. Eur J Endocrinol 2006;155:27-31.
Next Article: Patients with multiple thyroid nodules are as likely to have a thyroid carcinoma as are patients with a solitary nodule |
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| Thyroid Digest Index | | | November 2006 Thyroid Digest |
