Sonographically detectable echogenic foci in malignant pediatric thyroid nodules can be reliably classified on the basis of American College of Radiology Thyroid Imaging, Reporting and Data System, with punctate echogenic foci composing the most common subtype. These echogenic foci do not represent psammomatous calcifications most of the time; instead, more than half of the malignant thyroid nodules with echogenic foci contained stromal calcifications or sticky colloid.