Most common thyroid Cancer is
**Core Concept**
Thyroid cancer is a malignancy of the thyroid gland, which is a butterfly-shaped endocrine gland located in the neck. The most common type of thyroid cancer arises from the follicular cells of the thyroid gland.
**Why the Correct Answer is Right**
The most common type of thyroid cancer is Papillary thyroid carcinoma (PTC), accounting for approximately 80-85% of all thyroid cancer cases. PTC arises from the follicular cells of the thyroid gland and is characterized by the presence of papillary structures, which are finger-like projections of tumor cells. The mechanism of PTC involves the activation of the RAS-RAF-MEK-ERK signaling pathway, leading to uncontrolled cell growth and tumor formation.
**Why Each Wrong Option is Incorrect**
**Option A:** Follicular thyroid carcinoma (FTC) is the second most common type of thyroid cancer, accounting for approximately 10-15% of cases. While FTC is a significant type of thyroid cancer, it is not the most common type.
**Option B:** Medullary thyroid carcinoma (MTC) is a rare type of thyroid cancer that arises from the parafollicular cells (also known as C cells) of the thyroid gland. MTC accounts for approximately 3-5% of all thyroid cancer cases and is not the most common type.
**Option C:** Anaplastic thyroid carcinoma (ATC) is a rare and aggressive type of thyroid cancer that arises from the follicular cells of the thyroid gland. ATC accounts for approximately 1-2% of all thyroid cancer cases and is not the most common type.
**Clinical Pearl / High-Yield Fact**
Papillary thyroid carcinoma is often associated with radiation exposure, particularly in children and adolescents. This is because radiation can cause genetic mutations that lead to the development of PTC.
**Correct Answer: C. Papillary thyroid carcinoma.