Significance of low levels of thyroglobulin in fine needle aspirates from cervical lymph nodes of patients with a history of differentiated thyroid cancer.
OBJECTIVE
Measurement of thyroglobulin in the washout of lymph node (LN) fine needle aspirates is recommended in the follow-up of patients with differentiated thyroid cancer (DTC). The significance of low fine needle aspirates thyroglobin (FNATg) levels remains a question, which we addressed.


METHODS
Prospective study comparing FNATg with FNA cytology. Exploration of 34 DTC patients (53 cervical LNs), 26 non-thyroidectomized patients with a thyroid-unrelated cervical mass (negative controls) and 13 with 21 thyroid nodules (positive controls). The 12 DTC patients (19 LNs) with a malignant FNA cytology and/or high FNATg level received LN surgery (11 patients) or I(131)-iodine treatment (1 patient) and the outcome measure was pathological or scintigraphic evidence of DTC LN metastasis.


RESULTS
All 26 negative controls showed FNATg <1 ng/FNA and all 21 positive controls showed high levels of FNATg (127-210,000 ng/FNA, median 38,000). Among DTC patients in 25 LNs with a benign FNA cytology, FNATg was undetectable in 24 and low in 1 (6 ng/FNA); in 19 LNs with a malignant FNA cytology, FNATg was high in 17 (80-140,000 ng/FNA, median 7174 ng/FNA) and low in 2 (6.6 and 7.1 ng/FNA), which proved to be low Tg immunostaining oncocytic DTC metastasis; in 9 LNs with a non-informative cytology, FNATg was undetectable in 8 but 11,825 ng/FNA in 1, which proved a DTC metastasis. Measurement of FNA albumin demonstrated that contamination of FNA by serum proteins was negligible.


CONCLUSIONS
Low FNATg levels can indicate a DTC metastasis. It cannot be related to clinically relevant levels of serum Tg.
Borel
Anne-Laure
AL
Endocrinology, CHU Albert Michallon and Université Joseph Fourier, 38043 Grenoble, France.
Boizel
Robert
R
Faure
Patrice
P
Barbe
Geneviève
G
Boutonnat
Jean
J
Sturm
Nathalie
N
Seigneurin
Daniel
D
Bricault
Ivan
I
Caravel
Jean-Pierre
JP
Chaffanjon
Philippe
P
Chabre
Olivier
O
D018263:Adenocarcinoma, Follicular / Q000378:metabolism / Q000556:secondary; D000418:Albumins / Q000378:metabolism; D001323:Autoantibodies / Q000097:blood; D014408:Biomarkers, Tumor / Q000378:metabolism; D044963:Biopsy, Fine-Needle / Q000379:methods*; D002291:Carcinoma, Papillary / Q000378:metabolism / Q000556:secondary*; D002454:Cell Differentiation; D005500:Follow-Up Studies; D006801:Humans; D008198:Lymph Nodes / Q000378:metabolism / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000473:pathology; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013954:Thyroglobulin / Q000097:blood / Q000276:immunology / Q000378:metabolism*; D013964:Thyroid Neoplasms / Q000378:metabolism / Q000473:pathology*
D000418:Albumins; D001323:Autoantibodies; D014408:Biomarkers, Tumor; C006606:anti-thyroglobulin; D013954:Thyroglobulin