Endocrine Abstracts

Introduction: Approximately 5–20% patients treated for differentiated thyroid carcinoma (DTC) develop metastases to the neck lymph nodes. Ultrasound-guided fine-needle aspiration biopsy (FNAB) is a routinely used method in the examination of suspicious lymph nodes. The measurement of thyroglobulin (Tg) levels in needle washout fluids (FNAB-Tg) has been reported to increase the diagnostic accuracy of FNAB.

Description of methods/designs: A total of 101 patients with lymphadenopathies who underwent surgery because of DTC were included in analysis. Ultrasound-guided FNAB and FNAB-Tg measurements of suspected lymph nodes were performed. FNAB-Tg levels were established by electrochemiluminescence (ECLIA). Results of microscopic examinations of FNAB smears and corresponding FNAB-Tg values were compared to the histology of removed lymph nodes and/or to clinical follow-up.

Results: All patients with positive cytology underwent surgery (n=19). Patients with elevated levels of FNAB-Tg and negative cytology underwent surgery (n=1), were treated with ¹³¹I (n=2) or were observed (n=1). In 19 of 21 patients with elevated levels of FNAB-Tg FNAB disclosed carcinoma cells. In the remaining two cases FNAB was not diagnostic. In five patients with positive cytology, FNAB-Tg levels were not elevated. Three of these patients presented with cervical lymphadenopathy shortly after thyroidectomy and two had cervical metastases from other malignancies.

Conclusions: Ultrasound-guided FNAB is not sensitive enough to detect all metastatic lymph nodes. FNAB-Tg measurement is an valuable adjunct to the cytological examination of suspicious neck lymph nodes, increasing its diagnostic accuracy. FNAB-Tg should be recommended for the management of metastatic lymphadenopathies in the follow-up of patients with DTC, particularly in difficult cases such as detecting of small and cystic metastases and in cases of indeterminate cytology.