This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Pathology
The feature that differentiate a follicular carcinoma from a follicular adenoma of thyroid is 
Select and explain. 
A. Nuclear pleomorphism, B. Huhle cell change, C. Capsular invasion, D. Absence of colloid
C: Capsular invasion
Answer: C: Capsular invasion 
Explanation: Follicular adenomas and carcinomas both are composed of well - differentiated follicular epithelial cells;the latter are distinguished by evidence of capsular and/or vascular invasion. They both have fairly uniform cells forming small follicles containing colloid. So there is no reliable cytological difference between them. (ref:ROBBINS Text book of pathology) REf img :