Medullary thyroid cancer (MTC) accounts for ~2–4% of all thyroid cancers and is biologically distinct from papillary and follicular thyroid cancers.
🧠 What makes MTC different?
Arises from parafollicular (C) cells, not follicular cells Produces calcitonin, a key tumor marker Does NOT respond to radioactive iodine Can be sporadic (~75%) or hereditary (~25%)
🧬 The genetic connection
Hereditary MTC is associated with RET mutations Seen in MEN2 syndromes (MEN2A, MEN2B, FMTC) All patients with MTC should undergo genetic testing, regardless of age or family history
🔍 How is MTC diagnosed?
Suspicious thyroid nodule on ultrasound Elevated serum calcitonin (often markedly high) Confirmed by FNA biopsy ± calcitonin washout Imaging to evaluate lymph node involvement
⚖️ How is MTC treated?
The cornerstone of treatment is surgery:
Total thyroidectomy Central neck lymph node dissection Lateral neck dissection when nodes are involved
➡️ Radioactive iodine has no role in MTC.
➡️ Targeted systemic therapies are used in advanced disease.
📈 Prognosis
Highly dependent on stage at diagnosis Early detection → excellent long-term outcomes Lymph node and distant spread worsen prognosis
🦋 Early recognition and expert surgical management are critical.
👨⚕️ Dr. Rodrigo Arrangoiz, MD
Surgical Oncologist – Thyroid, Head & Neck, Breast
Mount Sinai Medical Center
📌 Take-home message:
Medullary thyroid cancer is rare but requires prompt diagnosis, genetic evaluation, and expert surgical care.
📚 References
Wells SA et al. Revised ATA Guidelines for Medullary Thyroid Carcinoma. Thyroid Elisei R et al. Management of Medullary Thyroid Cancer. Lancet NCCN Guidelines: Thyroid Carcinoma
Rodrigo Arrangoiz MS, MD, FACS, FSSO 