Amyloid deposition is seen in which type of carcinoma thyroid: September 2009
**Core Concept**
Amyloid deposition is a characteristic histopathological feature of certain types of thyroid carcinomas, which can be associated with a distinct clinical presentation and prognosis. The deposition of amyloid proteins in these tumors can lead to a unique appearance under microscopic examination.
**Why the Correct Answer is Right**
Medullary thyroid carcinoma (MTC) is a type of thyroid cancer that arises from the parafollicular cells, also known as C-cells, which produce calcitonin. Amyloid deposition is a hallmark feature of MTC, and it is thought to be due to the production of amyloid precursor proteins by the tumor cells. This amyloid deposition can be detected using special stains such as Congo red, which exhibits a characteristic green birefringence under polarized light.
**Why Each Wrong Option is Incorrect**
**Option A:** Follicular thyroid carcinoma is a type of thyroid cancer that arises from the follicular cells, but it is not typically associated with amyloid deposition.
**Option B:** Papillary thyroid carcinoma is another common type of thyroid cancer, but it is characterized by the presence of papillary fronds and nuclear features such as pseudoinclusions, not amyloid deposition.
**Option C:** Anaplastic thyroid carcinoma is a highly aggressive type of thyroid cancer, but it is not typically associated with amyloid deposition.
**Clinical Pearl / High-Yield Fact**
MTC is often associated with a genetic predisposition, particularly in families with a history of the MEN2 syndrome, and early detection and treatment can significantly improve prognosis.
**Correct Answer:** D. Medullary thyroid carcinoma