Surgical Science, 2013, 4, 494-499
Published Online November 2013 (http://www.scirp.org/journal/ss)
Open Access SS
Accuracy of Fine Needle Aspiration Cytology of Solitary
Thyroid Nodules in Tertiary versus Community Hospital
H. M. El Hennawy1, H. O. Abu Zaid2, Imaad Bin Mujeeb3, Eihab A. El Kahlout4, El S. M. Bedair5
1Trauma Surge ry Department, Hama d General Hospital, Hamad Medical Corporation, Doha, Qatar
2Medicine Department, Al Khor Hospital, Hamad Medical Corporation, Doha, Qatar
3Pathology Department, Hamad General Hospital, Hamad Medi cal Corporation, Doha, Qatar
4Surgery Department, Al Khor Hospital, Ham ad Med ical Corporation, Doha, Qatar
5Radiology Department, Al Khor Hospital, Hamad Medical Corporation, Doha, Qatar
Received October 11, 2013; revised November 2, 2013; accepted November 10, 2013
Copyright © 2013 H. M. El Hennawy et al. This is an open access article distributed under the Creative Commons Attribution Li-
cense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Background: Fine needle aspiration cytology (FNAC) is considered as the gold standard diagnostic test for the diagno-
sis of solitary thyroidnodules (STN). Aim: To compare the accuracy of FNAC in diagnosis of thyroid nodules in Al
Khor community hospital versus that of tertiary hospital (Hamad General Hospital) in Qatar. Methods: Retrospective,
descriptive and comparative study of 320 patients of any age group and both sexes who have thyroid nodules and are
subjected to surgical treatment [160 patients from Al Khor community hospital (group A) and 160 patients from Hamad
General Hospital (group B)] during the period from May 2005 to Dec 2012. Each group was subdivided into free hand
FNAC (done by physicians) an d ultrasonography guided FN AC. All samples were prepared in the same h istopathology
laboratory and interpreted by the same histopathology team. Results: Free hand FNAC in group A and group B
achieved a sensitivity of (10% vs. 50 %), specificity of 93% in both groups, positive predictive valu e of (25% vs. 17%),
negative predictive value of (82% vs. 98%), and a total accuracy of (82% vs. 94%) respectively, while US guided
FNAC in group A and group B achieved a sensitiv ity of (10% vs. 86%), specificity of (98% vs. 94%), positive pred ic-
tive value of (50% vs. 60%), negative predictive value of (86% vs. 98%), and a total accuracy of (85% vs. 97%) respec-
tively. Conclusion: The overall accuracy of FNAC of STN in tertiary hospital was better than community hospital.
More training is required for community hospital staff.
Keywords: Needle Aspiration; Solitary Thyroid Nodules; Accuracy
Thyroid nodules are common clinical findings and have a
reported prevalence of 4% - 7% of adult population.
However, fewer than 5% of adult thyroid nodules are
malignant, and the vast majority is non-neoplastic lesions
. Solitary thyroid nodule (STN) is defined clin ically as
the localized thyroid enlarg ement with apparently normal
rest of the gland. The main goal of evaluating these nod-
ules is to identify nodules with malignant potential .
FNAC is safe, simple and quick with a low complication
rate so considered as the gold standard initial investiga-
tion in the diagnosis of thyroid swellings [3-5]. With the
increase use of imaging over the last decades, the number
of incidentally discovered thyroid nodules is rising .
Either palpation (free hand) or ultrasonography (US) may
be used for guidance of FNA, but US has several advan-
tages over palpation [7,8]. Limitations of FNAC include
false negative and false positive results and a proportion
of FNA results that are not obviously benign or malig-
nant and fall into the indeterminate or suspicious group
. Moreover, the pitfalls of FNAC are related to speci-
men adequacy, sampling techniques, the skill of the ph y-
sician performing the aspiration, the experience of the
pathologist interpreting the aspirate and the overlapping
cytological features between some benign and malignant
thyroid lesions . No previous researchers studied if
the level of hospital (community or tertiary) affects the
accuracy of FNAC. This study aimed to compare the
accuracy of FNAC in STN in a tertiary versus commu-
nity hospitals and to determine the possible reasons of
differences in accuracy if present.
H. M. EL HENNAWY ET AL. 495
This is a retrospective comparative descriptive study of
320 Consecutive diagnosed cases of STN treated surgi-
cally from two hospitals; 160 patients from Al Khor
community Hospital (group A) and 160 patients from
Hamad General tertiary Hospital (group B) during the
period from May 2005 to Dec 2012. Informed consents
were taken from all patients. Institution research com-
mittee approved the study. Detailed history, physical
examination, thyroid function tests, neck ultrasonography,
FNAC, surgical intervention and post-operative histopa-
thology were reviewed. All cytological and postoperative
histopathology specimens were prepared in the same
cyto/histopathology laboratory and interpreted by same
cyto/histopathology team. Each group was subdivided
into free hand FNAC (done by surg eons in the outpatient
clinic) and ultrasonography guided FNAC. Free hand
FNAC were performed using aspiration technique when
a 23-gauge needle was connected to a 10-ml syringe
mounted on a syringe holder. Multiple needle passes
were made within the lesion 3 - 4 times at varying angles
and depths and with constant negative pressure (never
emerging outside the skin). Before final withdrawal, the
negative pressure was released prior to the needle
emerging from the skin. The cytological material was
transferred on to glass slides. For US-guided FNAC
Technique, after the lesion is localized using a high-
resolution (7.5 - 15 MHz) linear-array transducer, the
patient is instructed not to swallow or speak during the
insertion of the needle. A freehand biopsy technique is
used, and the syringe attached to the needle is placed just
above the transducer. During the procedure, all needle
movements should be continuously visualized in real
time. It is recommended that aspiration be performed at
least twice. Before aspiration, scanning is performed in
the transverse plane for lesion localization, followed by
color Doppler mapping to depict any large blood vessels
in and around. The collected material is placed on four
glass slides, smeared, and fixed in 95% ethyl alcohol for
about 30 minutes. All the slides were stained with Pa-
panicolaou stain. We categorized our results into insuffi-
cient for diagnosis, benign, atypical follicular lesion of
undetermined significance, follicular neoplasm, suspi-
cious for malignancy, and malignant sampling according
to the recent Bethesda classification . The smear was
considered adequate if there were at least five groups of
well-visualized follicular cells, each group containing ten
or more cells . All patients subsequently had a thy-
roid resection and a definitive diagnosis was reached
FNAC results were then compared with the definitive
histological diagnosis which was considered the gold
standard. No blinding was done, in Al Khor community
hospital group (A) we included all STN FNAC speci-
mens during the study period while in tertiary hospital
group (B) we included only the first consecutive 160
FNAC specimen done during the same period. Follicular
neoplasm Specimens were excluded from our results. We
studied the details of inconclusive specimen.
We excluded patients with inconclusive and follicular
adenoma/neoplasm results. Total number of Group A
specimens became 120 vs. 134 in group B. Free hand
FNAC was 55 in group A vs. 64 in group B. US guided
FNAC was 65 in group A vs. 70 in group B. We com-
pared the results of free hand FNAC and US guided
FNAC in both hospitals separately. Data were analyzed
statistically using SPSS software to assess the sensitiv ity,
specificity and accuracy of the result. Diagnostic accu-
racy represents combination of sensitivity and specificity.
The FNAC results in community hospital group A vs.
tertiary hospital group B included; benign diagnosis in
[114 patients (71.2%) vs. 123 (76.8%)], malignant in [6
patients (3.7%) vs. 11 (6.8%)], follicular neoplasm in 9
patients (5.6%) vs. 8 (5%)] and inconclusive specimens
in 31 patients (19.4%) vs. 18 (11.2%)] (Table 1).
Inconclusive specimens in free hand FNAC were 29%
and 15% in group A and B respectively, while in US
FNAC were 10% and 6.25% in group A and B respec-
tively. Free hand FNAC repeated twice in group A and
group B was (15% vs. 10%) while US FNAC repeated
twice in group A and group B was (6% vs. 5%). 90% of
the repeated FNAC revealed satisfactory results. The
remaining 10% (5 patients) underwent total thyroidec-
tomy; 3 of them were papillary carcinoma. We excluded
patients with inconclusive and follicular adenoma/neo-
plasm results. Total number of Group A specimens be-
came 120 vs. 134 in group B. Free hand FNAC was 55 in
group A vs. 64 in group B. US guided FNAC was 65 in
group A vs. 70 in group B. FNAC results were compared
to that of postoperativ e histopathology. Free hand FNAC
in both groups (Table 2) and US guided FNAC in both
groups (Table 3).
Free hand FNAC in group A and group B achieved a
sensitivity of (10% vs. 50%), specificity of 93% in both
groups, positive predictive value of (25% vs. 17%),
negative predictive value of (82% vs. 98%), and a total
accuracy of (82% vs. 94%) respectively (Ta b le 4). While
in US guided FNAC in group A and group B achieved a
sensitivity of (10% vs. 86%), specificity of (98% vs.
94%), positive predictive value of (50% vs. 60%), nega-
tive predictive value of (86% vs. 98%), and a total accu-
racy of (85% vs. 97%) respectively (Table 5).
In current study, we can notice a significant differen ce in
accuracy of FNAC of STN in tertiary versus community
hospital. While the sensitivity of free hand FNAC in the
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H. M. EL HENNAWY ET AL.
Table 1. Results of FNAC.
FNAC Results Group A Group B
Inconclusive 31 (19.4%) 18 (11.2%)
Follicular adenoma/neoplasm 9 (5.6%) 8 (5%)
Non Hodgkin lymphoma
Table 2. Free hand FNAC.
Group A free hand FNAC
Benign (n 51)
malignant (n 4)
42 (TN) 9 (FN)
1 (FP) 3 (TP)
Group B free hand FNAC
Benign (n 59)
malignant (n 5)
56 (TN) 3 (FN)
1 (FP) 4 (TP)
TN: true negative; FN: false ne gative; TP: true positive; FP: false positive.
Table 3. US Guided FNAC.
Group A US Guided FNAC
Benign (n 63)
malignant (n 2)
54 (TN) 9 (FN)
1 (FP) 1 (TP)
Group B US Guided FNAC
Benign (n 64)
malignant (n 6)
63 (TN) 1 (FN)
1 (FP) 5 (TP)
TN: true negative; FN: false ne gative; TP: true positive; FP: false positive.
tertiary hospital was higher than that of the community
hospital (50% and 10% respectively), both groups had
similar specificity (93%). Moreover the tertiary hospital
had higher negative predictive and total accuracy values.
Similarly, US guided FNAC in tertiary hospital achieved
higher sensitivity, po sitive predictive, negative pred ictive
and accuracy values.
Despite FNAC has about 95% accuracy in distin-
guishing between benign and malignant thyroid nodules,
FNAC is unable to distinguish between benign and ma-
lignant follicular lesions in the absence of nuclear fea-
tures of papillary carcinoma. The indeterminate diagno sis
of follicular neoplasm encompasses a number of hetero-
geneous thyroid lesions including cellular adenomatoid
nodule, follicularaden oma, and follicular carcinoma .
Table 4. Free hand FNAC.
Total 55 64
M/F 18/37 22/42
Mean age 44 47
False negative rate0.17 0.08 - 0.31 0.01 0.001 - 0.09
False positive rate0.75 0.22 - 0.98 0.83 0.36 - 0.99
Prevalence 0.18 0.09 - 0.31 0.03 0.005 - 0.1
Sensitivity 10% 0.005 - 0.46 50% 0.03 - 0.97
Specificity 93% 0.80 - 0.98 93% 0.83 - 0.97
value 25% 0.01 - 0.78 17% 0.009 - 0.63
value 82% 0.69 - 0.91 98% 0.90 - 0.99
Total accuracy 82% 94%
Table 5. US guided FNAC.
Total 65 70
M/F 25/40 19/51
Mean age 41 45
False negative rate0.14 0.07 - 0.26 0.01
False positive rate0.5 0.03 - 0.97 0.6
Prevalence 0.15 0.08 - 0.27 0.093 0.04 - 0.19
Sensitivity 10% 0.005 - 0.46 86% 0.42 - 0.99
Specificity 98% 0.8 9 - 0.99 94% 0.85 - 0.98
value 50% 0.03 - 0.97 60% 0.27 - 0.86
value 86% 0.74 - 0.93 98% 0.90 - 0.99
Total accuracy 85% 97%
In this study we excluded all cases of follicular neoplasm
to avoid this limitation as much as possible.
False negative and positive results were found par-
ticularly with small tumors and when there is associated
degenerative or inflammatory change in adjacent thyroid
tissue. In addition, th ere is a group of lesions which over-
lap benign and malignant features. For instance, the dis-
tinction between a cellular colloid goiter and a follicular
neoplasm may be impossible . FNAC false negative
rate (FNR) ranged from 1% to 16% in different series
[15-19]. Factors implicated for this rate include tech-
nique, slide preparation and interpretation of results by a
cytopathologist. It is also well recognized that certain
thyroid pathologies have similar cytological features
which make diagnosis extremely difficult [20,21].
In our series FNR for free hand FNAC were high in
both community and tertiary hospitals (17% and 14%
respectively) compared to 1% (FN) in US guided group
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H. M. EL HENNAWY ET AL. 497
in both hospitals.
FNAC false positive rate (FPR) indicates that a patient
with malignant FNAC result was found on histological
examination to have benign lesion. In our series the FPR
for free hand FNAC were significantly low in tertiary
hospital group for both free hand and US guided FNAC
(5% and 6% respectively) compared to higher values in
community hospital group for both free hand and US
guided FNAC (75% and 83% respectively) which agrees
with other series that ranged from 0% to 8% .
FNAC has inherent limitations related to inadequate
sampling, reportedly from 10% to 31% [22-24]. Speci-
men procurement may be affected by the level of opera-
tor experience, accuracy of localization of the lesion and
the needle, method of guidance (palpation or US), num-
ber of aspirations, needle gauge, sampling technique,
capability for immediate on-site cytologic analysis, and
many other factors. Unsatisfactory specimen may be due
to cystic fluid, bloody smears or poor technique in ob-
taining the sample and/or preparing the slides. The Pa-
panicolaou Society of Cytopathology task force on Stan-
dards of Practice recommends that aspirators who per-
sistently produce a high rate of unsatisfactory aspirates
(>15%) should be identified and given r emedial training.
To develop and maintain the necessary level of staff ex-
pertise in an institution, the number of staff members
who perform aspiration biopsies and the interpreting cy-
topathologists should be kept small. Each staff member
who performs aspiration biopsies must complete at least
1 - 5 such procedures per month . Criteria of speci-
men adequacy are: 1) aminimum of five or six groups of
well-preserved cells, with each group containing ap-
proximately 10 - 15 cells; 2) six clusters of benign cells
on at least two slides prepared from separate FNA biopsy
samples; 3) 10 clusters of follicular cells, with each clus-
ter containing at least 20 cells. Adherence to rigid criteria
leads to higher nondiagno stic rates and lower false-nega-
tive rates; and high nondiagnostic rates exacerbate pa-
tient anxieties and lead to the performance of unneces-
sary repeat aspiration and unnecessary surgical excision,
thereby reducing the overall efficiency and cost-effec-
tiveness of the FNA biopsy procedure . In our study,
Inconclusive specimens were higher in community hos-
pital for both free hand FNAC (29% vs. 15%) and US
FNAC (10% vs. 6.25%).
A large nodule is easier to sample than a smaller one,
and the diagnostic yield from FNA of large nodules may
be higher. Degirmenci et al. reported that the highest
specimen adequacy rate was observed among nodules
smaller than 1 cm (76.4%) and the lowest rate was ob-
served among nodules larger than 3 cm (56.9%). They
inferred that the lower rate in larger nodules probably
resulted from increased vascularity and the larger size of
blood vessels, with resultant blood staining of the mate-
rial acquired at fine needle biopsy . Another probable
cause of the inadequacy of specimens from larger nod-
ules in the study by Degirmenci et al. is that large nod-
ules more often are cystic and contain necrotic areas.
Selecting finer needles (24 - 25 G) for sonography-
guided FNB of thyroid nodules and using the capil-
lary-action technique decreased the rate of inadequate
material in cytological examination . One of the
limitations of this study was that we did not include the
STN size and site. Moreover we did not mention in can-
cer cases if the lesions originated from the same STN or
originated from other foci.
FNAC has high sensitivity and specificity for predict-
ing thyroid malignancies averaging 83% and 92% re-
spectively [27,28]. Inpatients with thyroid nodules 4 cm
or larger, the FNAC results are highly inaccurate, mis-
classifying half of all patients with reportedly benign
lesions. Furthermore, those patients with a non diagnostic
FNAC result display a high risk of differentiated thyroid
carcinoma. Therefore, Scott N. Pinchot et al. recom-
mended that diagnostic lobectomy be strongly considered
in patients with thyro id nodules 4 cm or larger regard less
of FNAB cytologic test results . A possible way to
reduce such error is to do aspirations from different parts
which could reveal the typical nuclear features of papil-
lary carcinoma . The determinant factor for such a
wide range of sensitivity, specificity and accuracy may
be how the cytopathologists classify “suspicious” as well
as false positive and negative samples. Some authors
include follicular lesion in malignant/neoplastic group,
whereas others exclude them from the calculations. In
our study sensitivity rate was low compared to others as
three out of four (75%) “indeterminate” FNAC results
were later found to have malignancy on histological ex-
amination. This was desp ite adequ ate number of cells (by
definition) and suggests that the FNAC interpretation is
operator dependent. Our positive predictive values and
negative predictive values for both techniques in both
hospitals were comparable with published data [31,32].
The accuracy of US-guided FNA was significantly
higher than that of palpation-guided FNA (68% vs. 48%),
particularly for tumors smaller than 2 cm and those that
were cystic or in deep locations. In our study the total
accuracy of free hand FNAC was higher in tertiary hos-
pital (94% vs. 82%) similarly, total accuracy of US
guided FNAC was higher in tertiary hospital (97% vs.
US-guided FNA is the best available diagnostic pro-
cedure to evaluate thyroid nodules to submit to surgery
. Kim DW et al. showed a good adequacy and effi-
cacy of US-FNAC for thyroid nodules despite one-sam-
pling . Specimen adequacy is not dependent on the
vascularity and echogenicity of the sampled thyroid nod-
ule but on components such as cystic change, calcifica-
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H. M. EL HENNAWY ET AL.
tion, and fibrosis.
Similarity, in our study US guided FNAC had better
accuracy and less inconclusive results than free hand
One of the limitations of this study group is that it
comprised FNAC samples taken by different operators,
hence with varying sk ill levels and experience. Moreover,
patients’ selection process not similar in both hosp itals as
it is consecutive 160 patients in the community hospital
(all patients done in this hospital) and we selected ran-
domly 160 patients from the about 700 patients done in
the tertiary hospital.
It is anticipated that improvement in diagnosis will
develop from specific cytopathological training in thy-
roid FNAC, consideration of the cytopathologist per-
forming the aspiration biopsy, and the development of
immunohistochemical and molecular techniques applied
to the cytologic smears.
The overall accuracy of both free hand and US guided
FNAC in tertiary hospital was better than community
hospital. We recommend better training of community
hospital staff and encourage more liberal use of US
 S. A. Roman, “Endocrine Tumors. Evaluation of Thyroid
Nodule,” Current Opinion in Oncology, Vol. 15, No. 1,
2003, pp. 66-70.
 H. K. Zygnunt, “The Thyroid Gland and Thyroglossal
Tract: Short Practice of Surgery,” 24th Edition, Arnold,
London, 2004, pp. 784-786.
 P. Caruso and E. L. Muzzaferri, “Fine Needle Aspiration
Biopsy in the Management of Thyroid Nodules,” Endo-
crinology, Vol. 1, 1991, pp. 194-202.
 U. Handa, S. Garg, H. Mohan and N. Nagarkar, “Role of
Fine Needle Aspiration Cytology in the Diagnosis and
Management of Thyroid Lesions: A Study on 434 Pa-
tients,” Journal of Cytology, Vol. 25, No. 1, 2008, pp. 13-
 M. Amrikachi, I. Ramzy, S. Rubenfeld and T. M. Whee l e r,
“Accuracy of Fine Needle Aspiration of Thyroid: A Re-
view of 6226 Cases and Correlation with Surgical and
Clinical Outcome,” Archives of Pathology & Laboratory
Medicine, Vol. 125, 2001, pp. 484-488.
 N. Coorough, K. Hudak, D. Buehler, S. Selvaggi, R. Sip-
pel and H. Chen, “Fine Needle Aspiration of the Thyroid:
A Contemporary Experience of 3981 Cases,” Journal of
Surgical Research, Vol. 170, No. 1, 2011, pp. 48-51.
 P. W. Wiest , M. F. Hartshorne and P. D. Inskip, “Thyroid
Palpation versus High-Resolution Thyroid Ultrasonogra-
phy in the Detection of Nodules,” Journal of Ultrasound
in Medicine, Vol. 17, No. 8, 1998, pp. 487-496.
 K. M. Clary, J. L. Condell and Y. Liu, “Interobserver
Variability in the Fine Needle Aspiration Biopsy Diagno-
sis of Follicular Lesions of the Thyroid Gland,” Acta Cy-
tologica, Vol. 49, No. 4, 2005, pp. 378-382.
 H. Galera-Davidson, “Diagnostic Problems in Thyroid
Fine Needle Aspirations,” Diagnostic Cytopathology, Vol.
17, No. 6, 1997, pp. 422-428.
 Z. W. Baloch, M. J. Sack, G. H. Yu, V. A. Livolsi and P.
K. Gupta, “Fine Needle Aspiration of Thyroid an Institu-
tional Experience,” Thyroid, Vol. 8, No. 7, 1998, pp. 565-
 E. S. Cibas and E. Z. Ali, “The Bethesda System for Re-
porting Thyroid Cytopathology,” Thyroid, Vol. 19, No.
11, 2009, pp. 1159-1165.
 E. Saggiorato, P. R. De and M. Volante, “Characteriza-
tion of Thyroid ‘Follicularneoplasms’ in Fine-Needle As-
piration Cytological Specimens Using a Panel of Immu-
nohistochemical Markers: A Proposal for Clinical Appli-
cation,” Endocrine-Related Cancer, Vol. 12, No. 2, 2005,
pp. 305-317. http://dx.doi.org/10.1677/erc.1.00944
 E. A. Sinna and N. Ezzat, “Diagnostic Accuracy of fine
Needle Aspiration Cytology in Thyroid Lesions,” Journal
of the Egyptian National Cancer Institute, Vol. 24, No. 2,
2012, pp. 63-70.
 H. A. Nggada, A. B. Musa, B. M. Gali and M. I. Khalil,
“Fine Needle Aspiration Cytology of Thyroid Nodule(s):
A Nigerian Tertiary Hospital Experience,” Internet Jour-
nal of Pathology, 2006.
 D. C. Howlett, B. Harper, M. Quante, A. Berresford, M.
Morley, J. Grant, et al., “Diagnostic Adequacy and Ac-
curacy of Fine Needle Aspiration Cytology in Neck Lump
Assessment: Results from a Regional Cancer Network
Over a One Year Period,” Journal of Laryngology &
Otology, Vol. 121, No. 6, 2007, pp. 571-579.
 K. Jarvi, R. Mokka and M. Vorne, “Problems of Cancer
Diagnosis in Thyroid Nodules,” Acta Chirurgica Scandi-
navica, Vol. 154, 1988, pp. 93-96.
 P. Perros, Ed., “British Thyroid Association, Royal Col-
lege of Physicians. Guidelines for the Management of Thy -
roid Cancer,” Report of the Thyroid Cancer Guidelines
Update Group, 2nd Edition, Royal College of Physicians,
 B. Degirmenci, A. Haktanir, R. Albayrak, M. Acar, D. A.
Sahin, O. Sahin, A. Yucel and G. Caliskan, “Sonographi-
cally Guided Fine-Needle Biopsy of Thyroid Nodules:
The Effects of Nodule Characteristics, Sampling Tech-
nique, and Needle Size on the Adequacy of Cytological
Material,” Clinical Radiology, Vol. 62, No. 8, 2007, pp.
 M. R. Castro and H. Gharib, “Thyroid Fine-Needl e Aspi-
ration Biopsy: Progress, Practice, and Pitfalls,” Endocrine
Open Access SS
H. M. EL HENNAWY ET AL.
Open Access SS
Practice, Vol. 9, No. 2, 2003, pp. 128-136.
 M. Gupta, S. Gupta and V. B. Gupta, “Correlation of Fine
Needle Aspiration Cytology with Histopathology in the
Diagnosis of Solitary Thyroid Nodule,” Journal of Thy-
roid Research, 2010, Article ID: 379051.
 B. Mundasad, I. Mcallister, J. Carson and P. Pyper, “Ac-
curacy of Fine Needle Aspiration Cytology in Diagnosis
of Thyroid Swellings,” The Internet Journal of Endocri-
nology, Vol. 2, No. 2, 2006.
 M. Radetic, Z. Kralj and I. Padovan, “Reliability of Aspi-
ration Biopsy in Thyroid Nodes: Study of 2190 Operated
Patients,” Tumori, Vol. 70, No. 3, 1984, pp. 271-276.
 D. C. Howlett, B. Harper, M. Quante, A. Berresford, M.
Morley and J. Grant, “Diagnostic Adequacy and Accu-
racy of Fine Needle Aspiration Cytology in Neck Lump
Assessment: Results fro m a Regional Cancer Network over
a One Year Period,” Journal of Laryngology and Otology,
Vol. 121, No. 6, 2007, pp. 571-579.
 S. A. Kantasueb, K. O. Sukpan and P. O. Mahanupab,
“The Study of Thyroid Lesions and the Correlation be-
tween Histological and Cytological Findings,” Chiang
Mai Medical Journal, Vol. 49, No. 3, 2010, pp. 105-110.
 A. Bartolazzi, A. Gasbarri and M. Papotti, “Application
of an Immunodiagnostic Method for Improving Preopera-
tive Diagnosis of Nodular Thyroid Lesions,” Lancet, Vol.
357, No. 9269, 2001, pp. 1644-1650.
 C. Cappelli, I. Pirola, D. Cumetti, L. Micheletti, A. Tironi,
E. Gandossi, E. Martino, L. Cherubini, B. Agosti, M.
Castellano, C. Mattanza and E. A. Rosei, “Is the Antero-
posterior and Transverse Diameter Ratio of Nonpalpable
Thyroid Nodules a Sonographic Criteria for Recommend-
ing Fine-Needle Aspiration Cytology?” Clinical Endo-
crinology, Vol. 63, No. 6, 2005, pp. 689-693.
 M. Bouvet, J. I. Feldman and G. N. Gill, “Surgical Man-
agement of the Thyroid Nodule: Patient Selection Based
on the Results of Fine-Needle Aspiration Cytology,” La-
ryngoscope, Vol. 102, No. 12, 1992, pp. 1353-1356.
 J. Cap, A. Ryska, P. Rehorkova, E. Hovorkova, Z. Kere-
kes and D. Pohnetalova, “Sensitivity and Specificity of
the Fine Needle Aspiration Biopsy of the Thyroid: Clini-
cal Point of View,” Clinical Endocrinology, Vol. 51, No.
4, 1999, pp. 509-515.
 S. N. Pinchot, H. Al-Wagih, S. Schaefer, R. Sippel and H.
Chen, “Accuracy of Fine-Needle Aspiration Biopsy for
Predicting Neoplasm or Carcinoma in Thyroid Nodules 4
cm or Larger,” Archives of Surgery, Vol. 144, No. 7, 2009,
pp. 649-655. http://dx.doi.org/10.1001/archsurg.2009.116
 X. J. Cai, N. Valiyaparambat h, P. Nixon, A. Waghorn, T.
Giles and T. Helliwell, “Ultrasound-Guided Fine Needle
Aspiration Cytology in the Diagnosis and Management of
Thyroid Nodules,” Cytopathology, Vol. 17, No. 5, 2006,
 T. Yokozawa, S. Fukata and K. Kuma, “Thyroid Cancer
Detected by Ultrasound-Guided Fine-Needle Aspiration
Biopsy,” World Journal of Surgery, Vol. 20, No. 7, 1996,
pp. 848-853, Discussion 853.
 L. F. Morris, N. Ragavendra and M. W. Yeh, “Evidence-
Based Assessment of the Role of Ultrasonography in the
Management of Benign Thyroid Nodules,” World Journal
of Surgery, Vol. 32, No. 7, 2008, pp. 1253-1263.
 B. T. Torres, G. M. Castro, L. I. Cucalón, B. C. Santaren,
J. De Diego and R. E. Larreina, “The Accuracy of Fine
Needle Aspiration Cytology in the Thryroid Nodule S tu dy,
in a Tertiary Hospital,” Endocrine Abstract s, Vol. 22, 2010,
 D. W. Kim, H. J. Choo, J. S. Park, E. J. Lee, S. H. Kim, S.
J. Jung and J. H. Ryu, “Ultrasonography-Guided Fine-
Needle Aspiration Cytology for Thyroid Nodules: An Em -
phasis on One-Sampling and Biopsy Techniques,” Diag-
nostic Cytopathology, Vol. 40, Suppl. 1, 2012, pp. E48-