Results of preoperative ultrasound guided fine needle aspiration biopsy of solitary thyroid nodules as compared with the histology. A retrospective analysis of 538 patients.
OBJECTIVE
The goal of this study was to assess the accuracy and limitations of ultrasound guided fine-needle aspiration biopsy (ug-FNAB) of solitary thyroid nodules.


METHODS
The ug-FNAB results of 538 patients with solitary thyroid nodules, who afterwards underwent thyroid surgery, were compared retrospectively with the histology. Patients with multinodular goiter were excluded from the study. Ug-FNAB was performed on growing and/or hypoechoic and/or hypofunctional nodules. The ug-FNAB results were grouped as follows: group 1: malignant (n = 44); group 2: malignancy cannot be ruled out (n = 173); group 3: non-malignant (n = 296), group 4: inadequate (n = 25).


RESULTS
When the cytological results of group 1 and group 2 were interpreted as being malignant and those of group 3 as being benign, sensitivity, specificity and accuracy of ug-FNAB were 96.7%, 65.8% and 69.5% respectively. The 62 thyroid carcinomas (TC) biopsied presented in 59 cases a suspicious or malignant cytology (95.2%). The smallest TC diagnosed by ug-FNAB had a diameter of 0.5 cm and 36.4% of all papillary TC < or = 1 cm displayed stage pT4. The histology verified a TC in 18 cases out of the 173 ug-FNABs in group 2. Non-malignant ug-FNABs were confirmed by histology in 294 patients (99.3%) in group 3. In 4.65% of the ug-FNABs inadequate material was aspirated.


CONCLUSIONS
Nodules with non-suspicious ug-FNAB results can be safely followed-up by sonography, as the cytological diagnoses were verified in more than 99% by histology. Papillary TC can be diagnosed with ug-FNAB very accurately. As stage pT4 was present in more than one third of patients with papillary TC < or = 1 cm, ug-FNAB is also recommended for thyroid nodules 0.5-1 cm in diameter located adjacent to the thyroid capsule. However, microfollicular proliferations remain the limitation of ug-FNAB, as the cytology cannot distinguish between benign adenoma and follicular TC.
Mikosch
P
P
Department of Nuclear Medicine and Endocrinology, State Hospital Klagenfurt, Austria. NuclMed.Abteilung@lkh-klu.at
Wartner
U
U
Kresnik
E
E
Gallowitsch
H J
HJ
Heinisch
M
M
Dinges
H P
HP
Lind
P
P
D018263:Adenocarcinoma, Follicular / Q000000981:diagnostic imaging / Q000473:pathology; D001707:Biopsy, Needle; D002291:Carcinoma, Papillary / Q000000981:diagnostic imaging / Q000473:pathology; D006652:Histological Techniques; D006801:Humans; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013961:Thyroid Gland / Q000000981:diagnostic imaging / Q000473:pathology*; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology; D016606:Thyroid Nodule / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D014463:Ultrasonography