Cytopathological review of patients that underwent thyroidectomies based on the diagnosis of papillary thyroid carcinoma by fine needle aspiration cytology but were later found to have benign tumors by histopathology.
OBJECTIVE
The aim of this study is to evaluate the specificity of diagnosing PTC by fine needle aspiration (FNA) cytology.


METHODS
This study retrospectively reviewed the cytopathological reports of 1066 patients that underwent thyroidectomy based on a diagnosis of PTC by FNA between January 1993 and December 2008. This study re-evaluated the cytology and histopathology of the patients that received false positive diagnoses of PTC by FNA.


RESULTS
Ten patients (0.9 %) received false positive diagnoses of PTC by FNA. Three patients were overdiagnosed as having PTC by FNA cytology. In contrast, the nuclear features of PTC in the other seven cases were confirmed by the retrospective reviews of the patients' FNA cytology. Three of the seven patients showed follicular structures in their resection specimens, thus resulting in a diagnosis of either adenomatous goiter or follicular adenoma. However, PTC could not be diagnosed by histopathology in the remaining four patients, even though the histopathology showed the nuclear features of PTC.


CONCLUSIONS
Most cases of PTC can be easily diagnosed by cytological and morphological atypia with certain limitations. The difficulty in diagnosing PTC by cytology is because the pathological features of PTC also occur in some benign thyroid tumors. Therefore, immunohistochemical or molecular biological approaches must be combined with current cytological diagnostic techniques for the diagnosis of PTC.
Division of Head and Neck Surgery, Cancer Institute Hospital, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo 135-8550, Japan.
Mutsukazu
M
Kitano
Iwao
I
Sugitani
Kazuhisa
K
Toda
Motoko
M
Ikenaga
Noriko
N
Motoi
Noriko
N
Yamamoto
Muneki
M
Hotomi
Yoshihide
Y
Fujimoto
Kazuyoshi
K
Kawabata
D000236:Adenoma / Q000175:diagnosis* / Q000473:pathology; D000328:Adult; D044963:Biopsy, Fine-Needle; D002291:Carcinoma, Papillary / Q000175:diagnosis* / Q000473:pathology*; D003581:Cytodiagnosis / Q000379:methods*; D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D005189:False Positive Reactions; D005260:Female; D006042:Goiter / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000473:pathology*