medullary thyroid carcinoma
A neuroendocrine tumor arising from thyroid parafollicular C cells that secrete calcitonin.
Full Definition
Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor that arises from the parafollicular C cells of the thyroid gland, which normally produce calcitonin. MTC accounts for approximately 3-5% of all thyroid cancers and can occur sporadically (75%) or as part of hereditary syndromes, particularly MEN2A and MEN2B. Elevated serum calcitonin and carcinoembryonic antigen (CEA) serve as tumor markers for diagnosis and surveillance. The tumor often presents as a thyroid nodule, and surgical treatment involves total thyroidectomy with central compartment lymph node dissection. Prognosis depends on stage at presentation, with hereditary forms often having better outcomes due to earlier detection through screening.
Usage
Usage note: MTC is acceptable abbreviation; always check for hereditary associations in younger patients.
In Context
- "Postoperative calcitonin levels remained elevated, suggesting residual medullary thyroid carcinoma." — Endocrinology follow-up note
- "The medullary thyroid carcinoma showed positive immunostaining for calcitonin and chromogranin A." — Pathology report