The feature that differentiate a follicular carcinoma from a follicular adenoma of thyroid is: (A) Nuclear pleomorphism, (B) Huhle cell change, (C) Capsular invasion, (D) Absence of colloid
Answer is C. 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 :