Clinical value of using ultrasound to assess calcification patterns in thyroid nodules.

BACKGROUND: Differentiating between benign and malignant thyroid nodules is important for providing appropriate treatment. In the present study we examined the clinical usefulness of ultrasound in examining calcification patterns in thyroid nodules, and thus predict malignancy.

METHODS: The records of 1,498 Chinese patients who underwent thyroidectomy for nodular thyroid disease were retrospectively examined. All patients underwent thyroid ultrasound within 1 month before surgery. Calcification patterns in thyroid nodules were examined, and tissue samples were analyzed to determine a pathological diagnosis. Calcifications were defined as macrocalcifications, microcalcifications, rim calcifications, or isolated calcifications.

RESULTS: A total of 2,122 thyroid nodules were examined, and 259 nodules (12.2%) were found to be malignant. Papillary carcinoma accounted for 85.3% of all malignancies. The majority of benign lesions were nodular goiters. Calcification was detected in 49.6% of malignant nodules and 15.7% of benign nodules. Microcalcifications were significantly more common in malignant nodules as compared to benign nodules (33.7 vs. 6.4%; P < 0.001). The sensitivity and specificity of microcalcifications for predicting malignancy were 33.7 and 93.6%, respectively, while the positive and negative likelihood ratios were 42.0 and 91.1%, respectively.

CONCLUSIONS: Calcifications, as detected by ultrasonography, are evident in benign and malignant thyroid nodules. Although microcalcifications are more common in malignant thyroid nodules than in benign ones, the clinical value of using the presence of microcalcifications alone for predicting malignancy is limited.