**Core Concept**
The presence of amyloid in the stroma of a thyroid nodule is a hallmark of medullary thyroid carcinoma (MTC), a type of thyroid cancer that originates from the parafollicular cells, also known as C-cells. This cancer is often associated with a familial syndrome, multiple endocrine neoplasia type 2 (MEN2).

**Why the Correct Answer is Right**
Medullary thyroid carcinoma is a malignant neoplasm that secretes calcitonin, a hormone that can be used as a tumor marker for this disease. The presence of amyloid in the stroma is a characteristic feature of MTC, which is formed from calcitonin and other peptides. The palpable cervical lymph node suggests regional lymph node metastasis, which is common in MTC. Therefore, the preferred treatment for this patient with MTC and lymph node metastasis is surgical resection of the thyroid gland and affected lymph nodes.

**Why Each Wrong Option is Incorrect**
* **Option A:** While radioactive iodine ablation is a common treatment for differentiated thyroid cancers, it is not effective for MTC due to its non-iodine avid nature.
* **Option B:** Chemotherapy is not the preferred treatment for MTC, especially in the absence of distant metastasis.
* **Option D:** External beam radiation therapy is not typically used as a primary treatment for MTC.

**Clinical Pearl / High-Yield Fact**
Amyloid deposition in the stroma of a thyroid nodule is a specific finding that should prompt further investigation for MTC, including calcitonin level measurement and genetic testing for MEN2.

**Correct Answer:** C. Surgical resection of the thyroid gland and affected lymph nodes.