Medullary thyroid cancer, also called medullary thyroid carcinoma (MTC), is one of the least common types of thyroid cancer. There are 4 forms (or types) of medullary thyroid cancer: sporadic, MEN 2A-associated, MEN 2B-associated, and familial. This article will go over the 4 forms of medullary thyroid cancer, giving the basics of each type.
The name of this form of medullary thyroid cancer gives a clue about what causes it to develop: it is sporadic, meaning that it develops randomly. It does not occur because of a family trait, and there is no genetic cause researchers can point to, saying, "This gene mutation is what makes people develop this form of medullary thyroid cancer."
Sporadic medullary thyroid cancer is the most common type of MTC.
Multiple endocrine neoplasia abbreviates to MEN, and there are several types of MEN. We have articles on MEN 1 and MEN 2 that thoroughly explain the different endocrine disorders involved in these syndromes.
Medullary thyroid cancer develops as part of MEN 2A. The other endocrine disorders associated with MEN 2A are: pheochromocytoma and hyperparathyroidism. People with MEN 2A have an inherited genetic mutation that leads to the development of this syndrome, and they have a much higher chance of developing medullary thyroid cancer.
MEN 2B includes medullary thyroid cancer, just like MEN 2A. Pheochromocytomas are also associated with MEN 2B, but unlike MEN 2A, there isn't any hyperparathyroidism.
MEN 2B includes physical characteristics, such as mucosal ganglioneuromas (also called mucosal neuromas), which are tumors at the end of the tongue. Tumors like this can also develop under the eyelid and in the gastrointestinal tract. Additionally, MEN 2B causes thicker lips and eyelids.
MEN 2B is caused by a genetic mutation that can be inherited—but it can also happen sporadically. That is, some people do not have a history of MEN 2B in their families, and yet they still develop it—and medullary thyroid cancer.
Familial, the fourth possible form of medullary thyroid cancer, can be inherited—hence the name. It can be passed down through the generations in a family.
Familial medullary thyroid cancer is different from MEN 2A- and MEN 2B-associated, which are also inherited. In familial medullary thyroid cancer, there aren't any other associated endocrine disorders; the medullary cancer appears on its own.
The sooner medullary thyroid cancer (medullary thyroid carcinoma) is caught—and the specific form is diagnosed—the better. Regardless of what form of MTC you have, treatment always includes a total thyroidectomy. If you have the MEN-associated forms of medullary thyroid cancer, you will definitely need other treatments for the other disorders. To learn more about treatments for the various forms of MTC, read our article on medullary thyroid cancer treatments.