Endocrine Surgery — MCQs

Question 331: A 26-year-old male presents to the outpatient department with a discrete thyroid swelling. On neck ultrasound, an isolated cystic swelling of the gland is seen. What is the risk of malignancy associated with this finding?

• A. 48%
• B. 12%
• C. 24%
• D. 3% (Correct Answer)

Explanation: ***3%*** - **Purely cystic thyroid nodules** (as described in this case with "isolated cystic swelling") have a **very low risk of malignancy**, typically **2-3%** or less. - According to **ATA guidelines** and **TIRADS classification**, purely cystic nodules are considered **low suspicion** lesions. - The cystic nature suggests a **benign process** such as a degenerated adenoma, colloid cyst, or simple cyst. - **Fine needle aspiration (FNA)** may still be considered if the nodule is >2 cm or has any suspicious solid components, but is often not required for purely cystic lesions. *48%* - This percentage is **significantly higher** than the actual malignancy risk for a purely cystic thyroid swelling. - Such a **high risk** would typically be associated with **solid nodules** exhibiting highly suspicious ultrasound features such as: - Microcalcifications - Irregular or spiculated margins - Taller-than-wide shape - Marked hypoechogenicity - Extrathyroidal extension *24%* - This percentage represents a **moderate to high risk** of malignancy, which is **not characteristic** of an isolated purely cystic thyroid swelling. - A risk in this range might be seen with: - **Mixed solid-cystic nodules** with predominantly solid components - Solid nodules with **intermediate suspicious features** on ultrasound *12%* - While lower than 24% or 48%, 12% is still **considerably higher** than the generally accepted malignancy risk for purely cystic thyroid nodules. - This risk level could be plausible for: - **Predominantly cystic nodules** with some eccentric solid components - Solid nodules with **mildly suspicious** features on ultrasound