Diagnosis of follicular neoplasm in thyroid nodules by fine needle aspiration cytology: does the result, benign vs. suspicious for a malignant process, in these nodules make a difference?
OBJECTIVE
To address the likelihood of thyroid malignancy for each cytologic interpretation, highly cellular and benign vs. follicular carcinoma, with particular attention to the indeterminate cytologic result, follicular neoplasm.


METHODS
We retrospectively reviewed thyroid nodule cytologic and histologic interpretations from 1994 to 2002 in a tertiary medical center setting. Patients were referred for evaluation of thyroid nodules found incidentally or on physical examination.


RESULTS
A total of 886 thyroid nodules were aspirated in 802 patients (500 benign, 195 indeterminate, 129 inadequate, 62 malignant). Of 195 indeterminate lesions, 180 were classified as follicular neoplasm or "cannot rule out/possible" follicular neoplasm, with 144 of these ultimately removed and with malignant histologic findings in 28. Any mention of follicular neoplasm in the cytology report conferred a 19.4% risk of malignancy in patients who went on to surgery (including an unexpected 18.2% rate of malignancy in the subcategory in which a possible follicular neoplasm was a secondary listing in an otherwise-benign cytologic differential diagnosis).


CONCLUSIONS
There was no difference in the likelihood of histologic malignancy between the cytologic subcategories of "definite "follicular neoplasm and "cannot rule out/possible" follicular neoplasm. We recommend that cytologic reports on fine needle aspiration of thyroid nodules with a diagnosis of follicular neoplasm reflect this fact.
Department of Endocrinology, National Naval Medical Center, Bethesda, Maryland 20889, USA.
Gregary D
GD
Marhefka
Jonathan D
JD
McDivitt
K M Mohamed
KM
Shakir
Almond J
AJ
Drake
D000236:Adenoma / Q000473:pathology* / Q000601:surgery; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle; D002291:Carcinoma, Papillary / Q000473:pathology* / Q000601:surgery; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D018570:Risk Assessment; D013964:Thyroid Neoplasms / Q000473:pathology* / Q000601:surgery; D016606:Thyroid Nodule / Q000473:pathology* / Q000601:surgery; D055815:Young Adult