Do hyperechoic thyroid nodules on B-ultrasound represent calcification?

OBJECTIVE: To explore the correlation between hyperechoic thyroid nodules observed on B-ultrasound and histological calcification seen in paraffin-wax sections.

METHODS: Records of patients who underwent surgical removal of thyroid nodules diagnosed on preoperative B-ultrasound were analysed retrospectively. Calcification present on B-ultrasound was compared with calcification seen in postoperative pathology specimens.

RESULTS: Of the 1,655 patients included in the study, 518 had malignant and 1,137 had benign thyroid nodules. Calcification on B-ultrasound was seen in 366 patients with malignant, and 414 with benign nodules. Calcification was confirmed on histology in 209 and 127 of these patients, respectively, giving a sensitivity and specificity for B-ultrasound in diagnosing calcification (compared with histology) of 95.87% and 47.67%, respectively, in thyroid cancer and 90.71%, and 71.21% respectively in benign thyroid nodules. Microcalcification was seen in 483 patients on B-ultrasound and in 186 on histology, of whom 294 (60.87%) and 152 (81.72%), respectively, had thyroid cancer.

CONCLUSIONS: B-ultrasound is a useful and accurate test for detecting calcification in thyroid nodules, with a high sensitivity. There is a close association between calcification (especially microcalcification) and thyroid cancer on both B-ultrasound and pathological examination.