Fig. 1Cytologic features of follicular adenoma (FA). (A) Low power view of fine needle aspiration cytology (FNAC) shows high cellularity composed of abundant microfollicles. (B) The crowded follicular cells have homogenous nuclear morphology composed of round nuclei, evenly dispersed, granular chromatin and faint nucleoli. (C) Microfollicles contain small amounts of colloid. (D) Hurthle cell type. The aspirate is very cellular and consists almost exclusively of Hurthle cells in small crowded arrangements. (E) Hurthle cell type. High-power view shows an abundant, finely granular cytoplasms and enlarged, variable sized, eccentrically located nucleus. (F) FNAC of follicular carcinoma (FC) confirmed by histologic diagnosis shows abundant syncytial clusters and small follicles similar to FA. (G) High-power view of FC shows more predominantly abundant, dispersed, isolated cells than FA in both cases. (H) FNAC (cytological misdiagnosis of Hurthle cell neoplasm [HCN]) of HCN with Hurthle cell change confirmed by histologic diagnosis shows abundant syncytial clusters composed exclusively of Hurthle cells. (I) Papillary carcinoma, oncocytic variant misdiagnosed as FA, with Hurthle cell type as determined by FNAC, showing definitive nuclear inclusion and mitosis. (J) Hashimoto's thyroiditis confirmed by histologic diagnosis misdiagnosed as FA, with Hurthle cell type as determined by FNAC, showing abundant Hurthle cells and a few lymphocytes.
Table 1.Clinical characteristics and findings of USG of the 36 cases of this study
Cases |
Sex/Age (yr) |
Site |
Size |
USG |
Histologic diagnosis |
1 |
F/17 |
L |
3.5 |
BN |
FA |
2 |
F/17 |
R |
1.7 |
BN |
FA |
3 |
M/61 |
R |
3.2 |
SM |
FA |
4 |
F/51 |
R |
1.7 |
SM |
FA |
5 |
F/18 |
L |
3.2 |
BN |
FA |
6 |
F/44 |
L |
4.5 |
BN |
FA |
7 |
F/25 |
L |
4.5 |
ID |
FA |
8 |
F/28 |
R |
1.9 |
ID |
FA |
9 |
F/35 |
R |
2.5 |
BN |
FA |
10 |
F/25 |
L |
1.5 |
ID |
FA |
11 |
F/36 |
R |
2.2 |
BN |
FA |
12 |
F/37 |
L |
1.6 |
ID |
NH |
13 |
F/66 |
L |
3.7 |
ID |
NH |
14 |
F/39 |
R |
2.5 |
SM |
FA |
15 |
F/64 |
R |
1.5 |
ID |
NH |
16 |
F/64 |
B |
- |
ID |
HT |
17 |
F/54 |
R |
4 |
ID |
FA |
18 |
F/36 |
I |
2 |
ID |
FA |
19 |
F/33 |
L |
2.4 |
ID |
FC |
20 |
F/62 |
R |
1.3 |
ID |
FA |
21 |
F/54 |
R |
0.6 |
SM |
NH |
22 |
F/30 |
L |
1.7 |
ID |
FA |
23 |
F/40 |
L |
0.5 |
ID |
HA |
24 |
F/44 |
R |
0.4 |
ID |
FA |
25 |
M/48 |
L |
2.5 |
ID |
HA |
26 |
F/40 |
L |
1 |
ID |
FA |
27 |
F/65 |
L |
0.3 |
ID |
NH |
28 |
F/70 |
R |
0.8 |
ID |
NH |
29 |
F/61 |
R |
0.6 |
ID |
NH |
30 |
F/39 |
R |
1.5 |
ID |
FC |
31 |
F/31 |
R |
1.6 |
ID |
FA |
32 |
F/51 |
L |
2 |
ID |
FA |
33 |
F/27 |
B |
1.1 |
ID |
PC |
34 |
F/48 |
R |
5 |
ID |
NH |
35 |
F/55 |
R |
3.5 |
ID |
HA |
36 |
F/62 |
R |
1.5 |
SM |
PC |
Table 2.Cytohistologic correlation of follicular neoplasm of thyroid
Cytologic diagnosis |
No. of cases (%) |
HD corresponds to FN (%)
|
HD corresponds to NFN (%)
|
FA |
HA |
FC |
Total |
NH |
PC |
HT |
Total |
FN |
33 (91.7) |
20 (55.6) |
3 (8.3) |
2 (5.6) |
25 (69.5) |
7 (19.4) |
1 (2.8) |
- |
8 (22.2) |
HCN |
3 (8.3) |
- |
- |
- |
- |
1 (2.8) |
1 (2.8) |
1 (2.8) |
3 (8.3) |
Total |
36 (100) |
20 (55.6) |
3 (8.3) |
2 (5.6) |
25 (69.5) |
8 (22.2) |
2 (5.6) |
1 (2.8) |
11 (30.5) |
Table 3.Cytologic features of thyroid follicular adenoma in FNAC
Cytologic features |
HD corresponds to FN (%)
|
HD corresponds to NFN (%)
|
p-valuea
|
FA (n = 20) |
HA (n = 3) |
FC (n = 2) |
Total (n = 25) |
NH (n = 8) |
PC (n = 2) |
HT (n = 1) |
Total (n = 11) |
High cellularity |
20 (100) |
3 (100) |
2 (100) |
25 (100) |
7 (87.5) |
1 (50) |
1 (100) |
9 (81.8) |
0.028*
|
Abundant microfollicles |
20 (100) |
3 (100) |
2 (100) |
25 (100) |
6 (75) |
1 (50) |
0 (0) |
7 (63.6) |
0.001*
|
Abundant cell crowding |
20 (100) |
3 (100) |
2 (100) |
25 (100) |
7 (87.5) |
1 (50) |
1 (100) |
9 (81.8) |
0.028*
|
Abundant dispersed isolated cells |
18 (90) |
3 (100) |
2 (100) |
23 (92) |
5 (62.5) |
2 (100) |
1 (100) |
8 (72.7) |
0.123 |
Homogenous nuclear morphology |
20 (100) |
0 (0) |
2 (100) |
22 (88) |
5 (62.5) |
0 (0) |
0 (0) |
5 (45.5) |
0.007*
|
Lack of nuclear grooves |
20 (100) |
2 (66.7) |
2 (100) |
24 (96) |
8 (100) |
1 (50) |
0 (0) |
9 (81.8) |
0.156 |
Lack of colloid material |
19 (95) |
3 (100) |
2 (100) |
24 (96) |
8 (100) |
2 (100) |
1 (100) |
11 (100) |
0.501 |
Lack of macrophages |
19 (95) |
3 (100) |
2 (100) |
24 (96) |
8 (100) |
2 (100) |
1 (100) |
11 (100) |
0.501 |