Which ultrasound features most strongly suggest a benign thyroid nodule?

• A. Spongiform appearance with well-defined margins and absence of microcalcifications
• B. Microcalcifications with irregular margins
• C. Tall, narrow shape with microcalcifications
• D. Hyperechoic lesion with blurred margins

Answer: (A)

A pattern that strongly suggests a benign thyroid nodule is a spongiform appearance with well-defined margins and no microcalcifications. The spongiform look comes from many tiny cystic spaces within the nodule, giving a honeycomb-like texture that is typical of benign colloid nodules. When the margins are clear and the nodule lacks microcalcifications, it further lowers the suspicion for cancer, since malignant nodules often show punctate microcalcifications and irregular, infiltrative borders.

In contrast, features such as microcalcifications, irregular or blurred margins, and a taller-than-wide shape raise concern for malignancy (such as papillary thyroid carcinoma) and would argue against a benign diagnosis.