This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thyroid Tumor, Subject name: Pathology
[{'content': 'A tumor similar to that shown in the illustration is observed in a biopsy specimen from the thyroid of a 50-year-old woman. An adjacent lymph node is also involved. Which of the following descriptions of this tumor is most appropriate? \nSelect and explain. \nA. Functional tumor resulting in thyrotoxicosis, B. Slow-growing lesion with relatively good prognosis, C. Origin from C cells, D. Calcitonin-producing tumor', 'role': 'user'}, {'content': 'Answer: B \nExplanation: - Given histopathological slide is showing well formed papillae with orphan Annie eye nuclei which are characteristic to papillary carcinoma of thyroid. - Papillary carcinoma is most common form of thyroid cancer. - It is associated with RET-PTC gene mutation & radiation exposure - These are slow growing tumors & often remains localized to thyroid, have an excellent prognosis, with a 10-year survival rate in excess of 95% - Papillary carcinoma is almost always nonfunctional & manifest most often as painless mass in neck.', 'role': 'assistant'}]