familial medullary thyroid carcinoma

pathology

Also known as: FMTC

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Last updated

July 20, 2026

Quick Summary

Familial medullary thyroid carcinoma (FMTC) is a hereditary form of thyroid cancer originating in the parafollicular cells (C cells) of the thyroid gland. These tumors are moderately malignant and can spread to other parts of the body. A key characteristic is hypercalcitoninemia, an elevated level of the hormone calcitonin in the blood, though this doesn't typically lead to low calcium levels.1

FMTC is often linked to inherited mutations in the RET proto-oncogene. These mutations can occur as part of a broader condition called multiple endocrine neoplasia type 2 (MEN2). Due to the hereditary nature and potential for early tumor development, individuals with a RET mutation often undergo thyroid removal at a young age to prevent cancer.12

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multiple endocrine neoplasia
MEN2
…75 percent of affected families), familial medullary thyroid carcinoma (FMTC-only; accounting for 5 to 20 percent of affected families), and MEN2B (accounting for less than 5 percent of affected families).
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…75 percent of affected families), familial medullary thyroid carcinoma (FMTC-only; accounting for 5 to 20 percent of affected families), and MEN2B (accounting for less than 5 percent of affected families).
Read More