Medullary ca of thyroid is associated with increase in?
First, I recall that MTC arises from the parafollicular C cells of the thyroid, which produce calcitonin. So, the most direct association here would be elevated calcitonin levels. That makes sense because when these cells become malignant, they secrete more calcitonin.
Now, the other options might be related to other thyroid cancers. For example, papillary or follicular carcinomas might involve TSH or thyroglobulin. But MTC specifically is linked to calcitonin. Also, MTC can be part of Multiple Endocrine Neoplasia type 2 (MEN2), which includes pheochromocytoma and hyperparathyroidism, but the question is about an increase, not the associated conditions.
Wait, maybe one of the options is CEA (Carcinoembryonic Antigen)? Some sources say that MTC can also show elevated CEA levels. But the primary marker is calcitonin. So if the options include calcitonin, that's the correct answer. If not, maybe CEA is a distractor. But the core concept here is calcitonin.
The wrong options could include things like TSH, T3, T4, which are more related to other thyroid conditions. For example, in hyperthyroidism, T3 and T4 are elevated, but that's not MTC. Or maybe thyroglobulin, which is a marker for follicular or papillary thyroid cancer.
So, the correct answer is calcitonin. The explanation should highlight that MTC is from C cells, which produce calcitonin, leading to increased levels. The other options are incorrect because they relate to different types of thyroid cancer or conditions. The clinical pearl would be that measuring calcitonin is key in diagnosing and monitoring MTC.
**Core Concept**
Medullary carcinoma of the thyroid (MCT) originates from parafollicular C-cells, which secrete **calcitonin**. Elevated serum calcitonin is a hallmark of this tumor, aiding in diagnosis and monitoring. The condition is also linked to **Multiple Endocrine Neoplasia type 2 (MEN2)** syndromes.
**Why the Correct Answer is Right**
Medullary thyroid carcinoma arises from C-cells that produce calcitonin. Tumor cells secrete **excessive calcitonin**, leading to increased serum levels. This is a key diagnostic marker; calcitonin levels rise early in the disease, even before clinical symptoms or imaging abnormalities appear. Additionally, calcitonin suppression tests are used to assess tumor activity.
**Why Each Wrong Option is Incorrect**
**Option A:** *TSH elevation* is seen in hypothyroidism, not MCT. **Option B:** *Thyroglobulin* is a marker for follicular or papillary thyroid carcinomas, not MCT. **Option C:** *Carcinoembryonic antigen (CEA)* may be elevated in MCT but is not diagnostic—calcitonin is the primary biomarker. **