Follicular variant of papillary thyroid carcinoma: diagnostic limitations of fine needle aspiration cytology.
OBJECTIVE
To study the diagnostic sensitivity and specificity of fine needle aspiration cytology (FNAC) offollicular variant of papillary thyroid carcinoma (FVPTC).


METHODS
The study group consisted of 390 papillary thyroid carcinoma (PTC) cases diagnosed histologically with thyroidectomy specimens. The FNAC and histopathologic classification were compared in terms of the appearance of FVPTC and non-FVPTC statistically with the chi squared test. Also, several features of the cytologic smears of FVPTC were reviewed.


RESULTS
Twelve of the 390 PTC cases were classified as FVPTC histologically. Five of the 12 cases were also reported as FVPTC in the diagnosis by FNAC and the other 7 as the usual type of PTC (UTPTC). There was 1 case classified as UVPTC histologically but FVPTC cytologically. If we use histologic diagnosis as the gold standard, the sensitivity and specificity of FNAC diagnosis of FVPTC were 42% and 83%, respectively.


CONCLUSIONS
FNAC may be a good tool for diagnosing PTC, but it is unreliable to differentiate between FVPTC and UTPTC.
Shih
Shyang-Rong
SR
Department of Internal Medicine, Far-Eastern Memorial Hospital, Taipei, Taiwan, ROC.
Shun
Chia-Tung
CT
Su
Deng-Huang
DH
Hsiao
Yung-Lien
YL
Chang
Tien-Chun
TC
D000293:Adolescent; D000328:Adult; D044963:Biopsy, Fine-Needle; D018265:Carcinoma, Papillary, Follicular / Q000175:diagnosis* / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000473:pathology