This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thyroid, Subject name: Surgery
Amyloid-rich stroma was seen on H&E stain of a thyroid nodule as shown below. What would be the diagnosis? 
Select and explain. 
A. Medullary thyroid carcinoma, B. Systemic amyloidosis, C. Thyroid lymphoma, D. Papillary thyroid carcinoma
A: Medullary thyroid carcinoma
Answer: A: Medullary thyroid carcinoma 
Explanation: Medullary Carcinoma of thyroid (MCT) Arise form para follicular 'C' Cells Derived from - Ultimobranchial bodies Secretes - calcitonin Level of calcitonin is raised Level of calcium is normal Clinical Features Midline swelling in anterior pa of neck Characteristic features Raised calcitonin History of diarrhea Presence of amyloid stroma Positive family history of Pheochromocytoma & Hyperparathyroidism (due to association with MEN 2A & MEN 2B)