Better Understanding in the Differentiation of Thyroid Follicular Adenoma, Follicular Carcinoma, and Follicular Variant of Papillary Carcinoma: A Retrospective Study

Table 2

Comparison of US features among the 231 thyroid nodules diagnosed as follicular adenoma, follicular carcinoma, and follicular variant of papillary thyroid carcinoma.

US features	Pathology			Total
	FA ( = 152)	FC ( = 25)	FVPTC ( = 54)
Composition					0.033
Solid	110 (72.4)	17 (68.0)	49 (90.7)	176 (76.2)
Mainly solid	38 (25.0)	6 (24.0)	4 (7.4)	48 (20.8)
Mainly cystic	4 (2.6)	2 (8.0)	1 (1.9)	7 (3.0)
Echogenicity					<0.001
Hyper/isoechoic	94 (61.8)	9 (36.0)	12 (22.2)	115 (49.8)
Hypoechoic	58 (38.2)	14 (56.0)	42 (77.8)	114 (49.3)
Markedly hypoechoic	0 (0.0)	2 (8.0)	0 (0.0)	2 (0.9)
Margin					<0.001
Circumscribed	143 (94.1)	20 (80.0)	30 (55.6)	193 (83.5)
Noncircumscribed	9 (5.9)	5 (20.0)	24 (44.4)	38 (16.5)
Calcifications					<0.001
Micro- or mixed	1 (0.7)	3 (12.0)	7 (13.0)	11 (4.8)
Macro- or eggshell	12 (7.9)	4 (16.0)	13 (24.0)	29 (12.6)
Negative	139 (91.4)	18 (72.0)	34 (63.0)	191 (82.6)
Shape					0.006
Parallel	149 (98.0)	23 (92.0)	47 (87.0)	219 (94.8)
Nonparallel	3 (2.0)	2 (8.0)	7 (13.0)	12 (5.2)
Final assessment					<0.001
Probably benign	136 (89.5)	13 (52.0)	26 (48.1)	175 (75.8)
Suspicious malignant	16 (10.5)	12 (48.0)	28 (51.9)	56 (24.2)

Note: percentages are in parentheses.