Medullary carcinoma of the thyroid (MTC) originates from parafollicular cells of thyroid

it is a rare malignant neuroendocrine tumor with low incidence but high malignancy. High-frequency ultrasound shows the characteristics of both malignant thyroid nodules and benign nodules. The lack of specific ultrasound findings makes differential diagnosis difficult. Elastography shows that the hardness of most MTC nodules is low

making it difficult to distinguish benign nodules. MTC patients with cervical lymph node metastasis are common

and their ultrasound findings are similar to those of lymph node metastasis in papillary thyroid carcinoma. Although fine needle aspiration biopsy has a low positive rate in the diagnosis of MTC

it is still the simpler

most accurate and eff

ective diagnostic method at present. The detection of calcitonin in the flushing fluid of the puncture combined with the examination of serum calcitonin and proto-oncogene

RET

is helpful for the accurate diagnosis of MTC.