Utility of Thyroglobulin measurement in fine-needle aspiration biopsy specimens of lymph nodes in the diagnosis of recurrent thyroid carcinoma

Abstract

IntroductionThe most common site for the metastasis of papillary carcinoma of the thyroid (PTC) is regional lymph nodes. Ultrasound (US) imaging may identify abnormal appearing lymph nodes, suspicious for PTC recurrence. Although fine needle aspiration biopsy (FNAB) of abnormal lymph nodes is often diagnostic of recurrence, small or cystic lymph nodes may be non-diagnostic due to lack of tumor cells. The measurement of thyroglobulin (TG) levels in FNAB specimens from lymph nodes suspicious for recurrent PTC can serve as an adjunct to the cytologic diagnosis.Materials and methods115 abnormal appearing lymph nodes were aspirated under ultrasound guidance in 89 patients with history of thyroid carcinoma. In addition to obtaining material for cytologic interpretation, an additional aspirate was obtained by FNAB and rinsed in 1 ml of normal saline for TG level measurements.ResultsThe cytologic diagnoses included: 35 (30%) reactive lymph node, no tumor seen (NTS), 39 (34%) PTC, 23 (20%) inadequate for evaluation due to lack of lymphoid or epithelial cells (NDX) 15 (13%) atypical/suspicious for PTC, and 3 (3%) other (e.g. paraganglioma, poorly differentiated carcinoma and carcinoma not otherwise specified). TG levels were markedly elevated (median 312 ng/ml; normal < 10 ng/ml) in 28 (72%) cases of PTC lymph node recurrence identified on cytology. TG measurements were also elevated in 5 lymph nodes classified as NTS and 4 NDX on cytology which resulted in 5 and 3 carcinoma diagnoses respectively on histological follow-up. Of the 9 atypical/suspicious cases with elevated TG levels all resulted in carcinoma diagnoses on follow-up.ConclusionThe measurement of TG in FNAB specimens from lymph node in patients with history of PTC is useful in detecting recurrent disease, especially in cases when the specimen is known to be or likely to be inadequate for cytologic evaluation.

Clinical impact of thyroglobulin (Tg) and Tg autoantibody (TgAb) measurements in needle washouts of neck lymph node biopsies in the management of patients with papillary thyroid carcinoma

“…We used the value of 10 ng/mL, which is consistent with the majority of published reports (11,14,(20)(21)(22).…”

“…The use of Tg-FNAB is well recognized as a valuable instrument in the examination of suspicious LN metastases (3,4,(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23). However, there are limited data regarding factors that may interfere with the diagnostic sensitivity of Tg-FNAB, such as the presence of TgAb in washout fluid samples.…”

“…These results may occur in cases of small or cystic LN metastases, which reflect a lack of tumor cells detected during the FNAB procedure (11). Nevertheless, the use of Tg-FNAB alone has several limitations, and despite being well established as an important tool in the investigation of suspicious LN metastases, Tg-FNAB presents variable results between metastatic and non-metastatic LNs (3,4,(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23). This subject has been the topic of recent reviews and meta-analysis studies (12,13).…”

Single-Session Treatment of Benign Cystic Thyroid Nodules with Ethanol versus Radiofrequency Ablation: A Prospective Randomized Study

“…In all patients, FNAC included aspiration of as much cystic fluid as possible by using a 23-gauge needle (15) and subsequent aspiration in the remaining solid portion or in the cyst wall. Benign cytologic results were determined according to the Bethesda classification system (18).…”

The Thyroglobulin: A Technically Challenging Assay for a Marker of Choice During the Follow-Up of Differentiated Thyroid Cancer

“…Conversely FNA-Tg is particularly usefull for the diagnosis of LN metastasis when these LN have cystic changes (Cignarelli et al, 2003;Baloch et al, 2008). FNA-Tg is more sensitive for detecting metastasis when compared with FNA cytology (FNA-C) alone and allows the accurate diagnosis for samples with non conclusive cytology (Giovanella et al, 2011).…”