[Usefulness of ultrasound in the diagnosis and management of well-differentiated thyroid carcinoma].

Thyroid nodules are found in the vast majority of the population, but only 5 to 10% are malignant. Ultrasonography of the thyroid, by virtue of being a straightforward, non-invasive method presenting strong correlation with macroscopic aspects of the thyroid gland, is being increasingly used to identify nodules that present a higher risk of malignancy. The presence of certain ultrasonographic characteristics such as hypoechogenicity, microcalcifications, irregular contours and central vascularization on Doppler, increase the risk of the lesion being malignant. Conversely, nodules presenting benign ultrasonographic characteristics such as hyperechogenicity and a mixed sponge-like aspect, and a concordant cytology, have a negative predictive value of 96.6%. It is, thus, important to examine all nodular lesions and to identify suspicious lesions that need biopsy, especially in multinodular glands. Ultrasonography is also highly sensitive in the identification of suspicious cervical lymph nodes during the follow-up of patients with thyroid carcinoma, even when PCI is negative and serum thyroglobulin (Tg) levels are undetectable. Tg measurement in the needle wash-out content is recommended as this has proven to be more sensitive than cytology in the diagnosis of cervical metastasis, especially where there is liquid content, and it is not affected by the presence of anti-Tg antibodies.