Diagnostic Utility of Thyroglobulin Detection in Fine-Needle Aspiration of Cervical Cystic Metastatic Lymph Nodes from Papillary Thyroid Cancer with Negative Cytology

Abstract

Cystic changes in metastatic cervical lymph nodes (CLN) from papillary thyroid cancer (PTC) may be a diagnostic pitfall in fine-needle aspiration biopsy (FNAB) cytology. We investigated in a series of CLN metastases from thyroid cancers (TC), including cystic PTC, and from a wide spectrum of extrathyroidal malignancies, the diagnostic role for metastatic TC of the rapid detection of thyroglobulin in eluates from FNAB (FNAB-Tg) of CLN. The study was carried out in a group of 79 subjects (22/57 M/F; median age, 56 years; range, 20-86 years) with enlarged CLN and thyroid nodules (TN), examined for potential metastatic TC, and harboring a large spectrum of incidentally diagnosed extrathyroidal malignancies (n = 24, mostly represented by lymphomas, lung, and breast cancers), CLN metastases from thyroid cancers (n = 28, including 6 cystic metastatic PTC), 6 specific lymphadenitis and 21 reactive lymphadenitis mostly detected (n = 16) during follow-up of patients with previously ablated TC. Markedly high FNAB thyroglobulin (Tg) values were found in all metastatic CLN TC. Two of the six cases with cystic metastatic CLN PTC were diagnosed by FNAB-Tg but not by cytology. In conclusion, FNAB-Tg has been confirmed as an easy modality and fast procedure to diagnose CLN metastasis from TC and high FNAB-Tg values with nondiagnostic cystic cytology strongly suggest cystic metastatic PTC.

Thyroglobulin measurements in washout of fine needle aspirates in cervical lymph nodes for detection of papillary thyroid cancer metastases

“…Despite the presence of specific characteristics of malignancy, such as cystic appearance, hyperechoic punctuations, loss of hilum and peripheral vascularization (9), the diagnosis of cervical LN metastases of DTC can be frequently complex, because inflammatory lymphadenopathies are extremely frequent in this region and, furthermore, metastasis in cervical LN from nonthyroid cancers is also relatively common (10). Therefore, US alone is not enough to distinguish a metastatic nodule from reaction hyperplasia (7).…”

Thyroglobulin detection in fine-needle aspirates of cervical lymph nodes: a technique for the diagnosis of metastatic differentiated thyroid cancer

“…A cystic mass caused by well-differentiated thyroid carcinoma (DTC) metastatic to a CLN has been shown not uncommonly to be the only presenting symptom in patients with an occult PTC (4,6,9,10).…”

Diagnóstico de metástases de carcinoma papilífero de tiróide através da dosagem de tiroglobulina no líquido obtido da lavagem da agulha utilizada na punção aspirativa

“…A partir de 1992, alguns grupos começaram a dosar a Tg no lavado da agulha utilizada para a punção de linfonodo suspeito, a fim de discriminar se o linfonodo seria reacional ou metastático (19)(20)(21)(22)(23)(24)(25). Pacini e cols.…”

“…Nesses pacientes, os autores estabeleceram um cut-off para que a dosagem de Tg-PAAF fosse discriminatória entre linfonodos reacionais ou metastáticos (25). Os demais trabalhos da literatura realizados com pacientes tiroidectomizados são concordantes em que, na ausência de tecido tiroidiano, os linfonodos reacionais apresentam níveis indetectáveis de Tg-PAAF (19,22,23). Novos estudos são necessários para melhor avaliação do comportamento da Tg-PAAF em linfonodos de pacientes não-tiroidectomizados (25).…”

“…Vários estudos têm mostrado que altos níveis de Tg-PAAF indicam a presença de metástase de CDT, enquanto que níveis indetectáveis de Tg-PAAF afastam essa possibilidade (19)(20)(21)(22)(23)(24)(25).…”