Which thyroid carcinoma has amyloid deposition-
**Core Concept**
Medullary thyroid carcinoma (MTC) is a type of thyroid cancer that originates from the parafollicular cells, also known as C-cells, which produce calcitonin. One of the characteristic features of MTC is the presence of amyloid deposition in the stroma, which can be detected by histopathological examination.
**Why the Correct Answer is Right**
Amyloid deposition in MTC is due to the secretion of calcitonin and other peptides by the tumor cells, which accumulate in the stroma and form amyloid fibrils. The presence of amyloid is a diagnostic hallmark of MTC and can be detected by immunohistochemical staining for calcitonin or other related peptides. The amyloid deposition is thought to be responsible for the characteristic "honeycomb" appearance of the tumor stroma.
**Why Each Wrong Option is Incorrect**
* **Option A:** Papillary thyroid carcinoma (PTC) is a different type of thyroid cancer that is characterized by the presence of papillae and psammoma bodies, but it does not typically show amyloid deposition.
* **Option B:** Follicular thyroid carcinoma (FTC) is a type of thyroid cancer that originates from the follicular epithelium, but it does not typically show amyloid deposition.
* **Option D:** Anaplastic thyroid carcinoma (ATC) is a highly aggressive type of thyroid cancer that can show a variety of histological features, but amyloid deposition is not a characteristic feature.
**Clinical Pearl / High-Yield Fact**
The presence of amyloid deposition in MTC is a diagnostic clue that can be used to differentiate it from other types of thyroid cancer. A high index of suspicion for MTC should be maintained in patients with a family history of MTC or multiple endocrine neoplasia (MEN) syndrome.
**Correct Answer:** C. Medullary thyroid carcinoma (MTC) is the correct answer.