Role of intrathyroidal calcifications detected on ultrasound as a marker of malignancy.

Objectives: Clinically palpable thyroid nodules are present in between 4% and 7% of the population, with only a small percentage of those harboring malignancy. Thus, it is important to find a cost-effective way to determine which nodules are more likely to be malignant. The purpose of this study was to evaluate the use of intrathyroidal calcifications detected on ultrasound as a risk factor for malignancy.

Study Design: Retrospective chart review.

Methods: One hundred fifty-nine patients with thyroid disease were included in this study. Patients were selected from a thyroid ultrasound (TUS) database. Charts were then reviewed, and only those patients who had a preoperative TUS and underwent surgery for tissue diagnosis were included.

Results: Of the 159 patients, 66 (41.5%) were diagnosed with cancer. Of those with malignancy, 52 (78.8%) had calcifications noted on TUS. Ninety-three of the patients were diagnosed with benign pathology. Of those 93 patients, 36 (38.7%) had TUS findings consistent with calcifications, whereas 57 (61.3%) did not. Statistical analysis using a chi-square test showed a strong association between cancer status and calcification, with P <.001. In our study, calcifications on TUS had a sensitivity of 78.8% and a specificity of 61.3%, with an odds ratio of 5.88.

Conclusion: The presence of calcifications detected on TUS should alert the physician for the possibility of malignancy, and further work-up should be pursued. This information may be used to improve the sensitivity of other diagnostic tests such as fine needle aspiration biopsies. Given the relatively low sensitivity and specificity of the test, its use alone as a marker of malignancy is limited, but it may be used in combination with other known risk factors and tests to decide on the most appropriate treatment plan.