Prevalence of Thyroid Cancer in Thyroid Nodules with Dense Calcification

Yoon, Jee Hee; Kim, Hee Kyung; Kim, Soo Jeong; Cho, Jin Seong; Kang, Ho Cheol

Abstract

BACKGROUND/AIMS
High-resolution ultrasonography has made it possible to predict thyroid cancers without invasive procedures. Densely calcified nodules are difficult to image on ultrasound, and considering them to be high risk features for thyroid cancers has been controversial. The aim of this study was to evaluate the prevalence of malignancy in patients with densely calcified nodules using an analysis of clinical parameters related to the development of thyroid cancer.
METHODS
We retrospectively reviewed the thyroid sonographic findings and clinical characteristics of patients with thyroid nodules who attended Chonnam National University Hwasun Hospital during a 5-year period (2,387 cases). Dense calcifications included coarse dense calcification and peripheral calcification (163 cases). Nodules with microcalcification (< 2 mm) were excluded from this analysis (154 cases). Ultrasonography-guided fine needle aspiration (FNA) was performed for all nodules with dense calcification.
RESULTS
Among the densely calcified nodules, 37 (22.7%) were malignant. The prevalence of malignancy in patients with densely calcified thyroid nodules was higher than that in patients without calcification (p < 0.01). The incidence of malignancy was greater in coarse calcified thyroid nodules than in nodules with peripheral (egg-shell) calcification, but this difference was not statistically significant (30.1% vs. 16.2%, p = 0.101).
CONCLUSIONS
Nodules with dense calcification carry a higher risk for malignancy than non-calcified nodules. Further, it is more difficult to obtain an adequate or diagnostic sample for nodules with dense calcification. Therefore, careful evaluation is necessary to diagnose malignancy in densely calcified nodules.