A well differentiated follicular carcinoma of thyroid can be best differentiated from a follicular adenoma by: (A) Huhle cell change, (B) Lining of tall columnar and cuboidal cells, (C) Vascular invasion, (D) Nuclear features
Answer is C. A well differentiated follicular carcinoma of thyroid can be best differentiated from a follicular adenoma by capsular invasion/ vascular invasion. This is not made out in FNAC and hence FNAC is not very useful. USG can make out this differentiating feature of follicular carcinoma. Reference : page 482 SRB's manual of surgery 5th edition