Bethesda System for Reporting Thyroid Cytopathology: A three-year study at a tertiary care referral center in Saudi Arabia

Table 1 The Bethesda system

Diagnostic category	Cytological diagnosis	Risk of malignancy, %	Usual management
I	Nondiagnostic or unsatisfactory	1-4	Repeat FNA with ultrasound guidance
II	Benign	0-3	Clinical follow-up
III	AUS/FLUS	5-15	Repeat FNA
IV	FNS/SFN	15-30	Surgical lobectomy
V	Suspicious for malignancy	60-75	Near-total thyroidectomy or surgical
VI	Malignant	97-99	Near-total thyroidectomy

FNA: Fine-needle aspiration; AUS/FLUS: Atypia of undetermined significance or follicular lesion of undetermined significance; FNS/SFN: Follicular neoplasm or suspicious for follicular neoplasm.

Table 2 Age and sex distribution of thyroid lesion (based on fine-needle aspiration cytology according to Bethesda system)

Age (yr)	Total number of patients	Gender	All FNAs (n = 1433) n, %
		F/M	Bethesda I	Bethesda II	Bethesda III	Bethesda IV	Bethesda V	Bethesda VI	Total
15-30	176 (14.8)	159/17	9 (4.5)	149 (74.9)	17 (8.5)	12 (6)	4 (2)	8 (4)	199
31-45	420 (35.4)	362/58	12 (2.4)	375 (74.7)	41 (8.2)	28 (5.6)	14 (2.8)	32 (6.4)	502
46-60	374 (31.5)	301/73	15 (3.3)	347 (75.1)	40 (8.8)	22 (4.8)	9 (2)	23 (5)	456
61-75	175 (14.7)	126/49	10 (4.5)	162 (72.3)	33 (14.7)	7 (3.1)	4 (1.8)	8 (3.6)	224
> 75	43 (3.6)	28/15	0	47 (90.4)	0	2 (3.8)	1 (1.9)	2 (3.8)	52
Total	1188	976/212	46 (3.2)	1080 (75.3)	131 (9.1)	71 (5)	32 (2.2)	73 (5.1)	1433

FNA: Fine-needle aspiration; F: Female; M: Male.

Table 3 Cyto-Histopathological correlation of thyroid lesion

Cytopathology	Histopathological diagnosis		Total
	Benign	Malignant, n (%)
Bethesda I	6	2 (25)	8
Bethesda II	165	16 (8.9)	181
Bethesda III	36	6 (14.3)	42
Bethesda IV	28	25 (47.2)	53
Bethesda V	8	18 (69.3)	26
Bethesda VI	2	57 (96.7)	59
Total	245	124 (33.6)	369

Table 4 Comparison rates of malignancy (%) on surgical resection for fine-needle aspiration diagnostic categories and malignancy risk of recent studies

	Published year	Comparison of diagnostic categories
		I (ND)	II (Benign)	III (AUS/FLUS)	IV (FN/SFN)	V (SM)	VI (malignant)
Recent studies
Park et al[22]	2014	13.3	40.6	9.1	0.4	19.3	17.6
Mondal et al[10]	2013	1.2	87.5	1	4.2	1.4	4.7
Mufti et al[29]	2012	11.6	77.6	0.8	4	2.4	3.6
Wu et al[30]	2012	20.1	39	27.2	8.4	2.6	2.7
Bongiovanni et al[31]	2012	2	54.7	6.3	25.3	6.3	5.4
Present study		3.2	75.3	9.1	5	2.2	5.1
Comparison of malignancy risk
Haugen et al[32] (meta-analysis)	2016	9-32	1-10	6-48	14-34	53-97	94-100
Pantola et al[33] 2016	2016	0	0	8.3	10	100	100
Park et al[22]	2014	35.3	5.6	69	50	38.7	98.9
Mondal et al[10]	2013	0	4.5	20	30.6	75	97.8
Mufti et al[29]	2012	20	3.1	50	20	80	100
Wu et al[30]	2012	12	8	27	33	68	100
Present study		25	8.9	14.3	47.2	69.3	96.7

ND: Nondiagnostic; AUS/FLUS: Atypia of undetermined significance/follicular lesion of undetermined significance; FN/SFN: Follicular neoplasm/suspicious for follicular neoplasm; SM: Suspicious for malignancy.

Table 5 Age and sex distribution of thyroid cancer

Age (yr)	Total number of nodules	Gender	All FNAs (n = 124) n, %
		F/M	Bethesda I	Bethesda II	Bethesda III	Bethesda IV	Bethesda V	Bethesda VI
15-30	18 (14.5)	3/15	0	3	1	3	4	7
31-45	49 (39.5)	39/10	1	5	2	9	7	25
46-60	43 (34.7)	35/8	1	7	3	9	5	18
61-75	12 (9.7)	8/4	0	1	0	3	2	6
> 75	2 (1.6)	2/0	0	0	0	1	0	1
Total	124	87/37	2 (1.6)	16 (12.9)	6 (4.8)	25 (20.2)	18 (14.5)	57 (46)

FNA: Fine-needle aspiration; F: Female; M: Male.

Table 6 Type and variants of thyroid cancer among histopathological diagnosis

Type of cancer	Total = 124 (n, %)	BETHESDA (n, %)
		I	II	III	IV (n = 25)	V	VI
PTC
Classic variant	57	1	5	1	3	8	39
Follicular variant	34	1	8	2	11	6	6
Conventional	19	0	2	2	3	3	9
Tall-cell variant	1	0	0	0	0	0	1
Total PTC	111 (89.6)	2	15	5	17 (68)	17	55
FTC
MIFTC	10	0	1	1	7	1	0
WIFTC	1	0	0	0	1	0	0
Total FTC	11 (8.9)	0	1	1	8 (32)	1	0
MTC	1 (0.8)	0	0	0	0	0	1
ATC	1 (0.8)	0	0	0	0	0	1

PTC: Papillary thyroid carcinoma; MTC: Medullary thyroid carcinoma; ATC: Anaplastic thyroid carcinoma; FTC: Follicular thyroid carcinoma; MIFTC: Minimally invasive follicular thyroid carcinoma; WIFTC: Widely invasive follicular thyroid carcinoma.