This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology and breast, Subject name: Surgery
A well Differenciated follicular carcinoma of thyroid can be best Differentiated from a Follicular Adenoma by 
Select and explain. 
A. Huhle cell change, B. Lining of tall columnar and cuboidal cells, C. Vascular invasion, D. Nuclear features
C: Vascular invasion
Answer: C: Vascular invasion 
Explanation: FNAC is is of limited value in the preoperative diagnosis of follicular thyroid cancer. Diagnosis of follicular thyroid cancer requires demonstration of cellular invasion of the capsule or vascular or lymphatic channels. Source : Sabiston 20th edition Pg : 905