the former two tumor types were distinguished by the presence of capsular invasion in encapsulated follicular carcinoma ( which was defined as lacking extension into the surrounding thyroid ) and by the frequent thinness of the capsule in follicular adenoma , while the latter two ( which both infiltrated adjacent thyroid or extrathyroid tissue ) were separated primarily on the basis of the tendency toward vesicular and hypochromatic nuclear staining in the follicular variant of papillary carcinoma , but with consideration of a number of other factors in addition .
C0151468
follicular adenoma
C0040132
thyroid