Thyroid Ultrasound > Top 10 Pathology > 5. Medullary Carcinoma

Medullary Carcinoma

Medullary thyroid cancer is a neuroendocrine tumor arising from the parafollicular C cells located in the upper two thirds of the thyroid gland. Although medullary cancer is associated with MEN2A (C-cell hyperplasia, pheochromocytoma, hyperparathyroidism), 80% occur sporadically. Ninety-five percent of patients who have MEN2A have C-cell hyperplasia and in 80% of affected patients, medullary thyroid carcinoma is the initial manifestation. Patients who have sporadic medullary carcinoma typically present with a painless palpable nodule in the fifth or sixth decade of life, but the disease is often metastatic to cervical lymph nodes at presentation. There is a slight female preponderance (1.5:1).

The value of serum calcitonin screening measurement in patients who have thyroid nodules is dubious because levels are often falsely elevated and FNA is highly accurate; however, calcitonin levels are useful once the diagnosis of medullary thyroid cancer has been established by cytologic evaluation.

On sonography, medullary carcinomas are typically solid, hypoechoic, and often have coarse central calcifications (image from Ultrasound Clinics Apr 2009).

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