Fine needle aspiration cytology of the thyroid: a cytohistologic study with evaluation of discordant cases.
OBJECTIVE
To analyze the diagnostic efficacy of fine needle aspiration cytology (FNAC) in the initial evaluation of thyroid nodules, with special emphasis on discrepant cytologic diagnoses.


METHODS
A total of 192 thyroid fine needle aspirates with subsequent histopathologic follow-up were analyzed. The cytologic diagnoses were divided into 4 categories: positive for malignancy, negative for malignancy, indeterminate for diagnosis and nondiagnostic. The detailed cytologic features were studied along with histopathology sections in all these cases by 2 observers (S.J. and P.D) independently.


RESULTS
Cytohistologic correlation was seen in 78.1% of cases and discordance in 21.9%. Indeterminate diagnoses accounted for 15.1% of cases. The majority of these were "follicular neoplasms." The overall sensitivity was 84.44% and specificity 99.11 %. A false positive diagnosis was made in 1 case (0.5%), proven a follicular adenoma on histopathologic examination. A false negative diagnosis was seen in 3.6% of cases. These were cases of papillary microcarcinoma.


CONCLUSIONS
FNAC is a safe, sensitive and specific technique in the initial evaluation of thyroid nodules. A correct cytologic diagnosis can be achieved in a majority of cases, thus obviating the need for a second surgical intervention. A careful and diligent search for various cytologic features and accurate sampling can help in reducing the number of indeterminate, false positive and false negative diagnoses.
Jogai
Sanjay
S
Department of Cytology, Kuwait Cancer Control Center, Sufat. sanjayjogai@rediffmail.com
Al-Jassar
Aisha
A
Temmim
Labiba
L
Dey
Pranab
P
Adesina
Aaron O
AO
Amanguno
H G
HG
D018263:Adenocarcinoma, Follicular / Q000473:pathology; D000328:Adult; D000368:Aged; D044963:Biopsy, Fine-Needle / Q000592:standards; D003937:Diagnosis, Differential; D003951:Diagnostic Errors / Q000517:prevention & control*; D004847:Epithelial Cells / Q000473:pathology*; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013961:Thyroid Gland / Q000473:pathology*; D013964:Thyroid Neoplasms / Q000473:pathology*; D016606:Thyroid Nodule / Q000473:pathology*