This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Medullary carcinoma thyroid arises from ? 
Select and explain. 
A. Parafollicular cells, B. Cells lining the acini, C. Capsule of thyroid, D. Stroma of the gland
A: Parafollicular cells
Answer: A: Parafollicular cells 
Explanation: Ans. is 'a' i.e., Parafollicular cells The unique feature of Medullary carcinoma thyroid is that unlike other carcinomas of thyroid they are not derived from the cells of the thyroid follicle, instead they are derived from calcitonin secreting parafollicular cells (C cells) which are neural crest derivatives. Thyroid neoplasm can arise from any of the cell types found within thyroid gland i.e. thyroid follicular cells, parafollicular cells (C cells), lymphocytes and stromal and vascular elements.