Session: SUN 459-496-Thyroid Neoplasia & Case Reports
Poster Board SUN-495
Our aim was to determine the comparable value of thyroglobulin in the washout of lymph node fine needle aspirate (FNATg) and fine needle aspiration biopsy (FNAB).
Materials and methods
We included 29 patients (37 FNAB) with previous history of differentiated thyroid cancer who underwent total thyroidectomy and were found to have suspicious cervical lymph nodes during follow-up. The referred population was evaluated on what concerns to gender, age, serum thyroglobulin, thyroglobulin antibodies, FNATg, FNAB and lymph node echographic features.
Cohort with 69% females; mean age of 45.9±15.1 years. Considering the serum thyroglobulin levels, 72% patients had disease’s persistence.
FNATg levels were undetectable (<1 ng/mL) in 40.5%, low (1.1-2.5 ng/mL) in 5.4% and high (54.3-155000 ng/mL) in 54.1% of samples. About 37.8% of FNAB results were benign, 35.1% non-diagnostic and 27% malignant.
All patients with undetectable FNATg had benign or non-diagnostic FNAB. On the group of malignant FNAB (n=9), eight had high levels of FNATg and one had a low level. Considering patients with non-diagnostic FNAB, 61.5% had high or low levels of FNATg.
After excluding the non-diagnostic FNAB, we obtained 88% of concordant results of FNATg and FNAB.
None of the patients with positive thyroglobulin antibodies and malignant FNAB had undetectable levels of FNATg.
Serum thyroglobulin correlates directly with FNATg, with a stronger correlation after excluding patients with detectable thyroglobulin antibodies (p-0.027 vs p-0.016). There was also a direct correlation between FNATg and benign/malign results on FNAB (Kruskal-Wallis test; p-0.011). No correlation between FNATg and lymph node echographic features was found.
In a patient with discordant FNATg and FNAB (high FNATg; benign FNAB), a surgical intervention confirmed the presence of metastasis. In this context, FNATg was of inestimable value, as it prevented further investigation that would delay cervical lymphadenectomy.
Positive thyroglobulin antibodies did not appear to influence FNATg levels.
The direct correlation found between FNATg and serum thyroglobulin as well as with FNAB results reinforces the relevance of this marker on patient’s assessment and therapeutic decision.
Nothing to Disclose: SG, CR, SP, MA, JS, CM, DG, FL, FC
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