Thyroglobulin detection in fine-needle aspirates of cervical lymph nodes: a technique for the diagnosis of metastatic differentiated thyroid cancer.
BACKGROUND
Fine-needle aspiration cytology is frequently used for differential diagnosis of neck masses of unknown origin. Inconclusive and even false-negative results are not uncommon.


OBJECTIVE
To evaluate the utility of thyroglobulin (Tg) measurement in fine-needle aspirates (FNA-Tg) for detecting cervical lymph node (CLNs) metastases from differentiated thyroid carcinomas.


METHODS
An ultrasound-guided fine-needle aspiration was done in 67 patients with 83 suspicious enlarged CLNs to obtain material for cytology and Tg measurement in the needle washout, using an immunometric chemiluminescent assay. Measurement of anti-Tg antibodies (FNA-TgAb) was also carried out in half of all the aspirates. Subjects were divided into two groups: one of 16 patients awaiting thyroidectomy and the other of 51 patients in follow-up after surgery.


RESULTS
The first group of patients had positive FNA biopsy (FNAB-Tg) in 14 out of the 18 studied CLNs with a range of 3.2-43 352 ng/ml, while FNAB-cytology indicated metastasis in only 8 out of the 14 CLNs with positive histology. A total of 65 CLNs were studied in the follow-up group. Lymphadenectomy was performed in 23 patients and 28 aspirated CLNs were removed. Histology confirmed the diagnosis of metastasis suggested by FNAB-Tg in 20 CLNs and of reactive lymphadenitis in the remaining 8 CLNs. FNAB-cytology was positive in only 11 CLNs. Sensitivity of FNAB-Tg was not affected by the studied FNAB-TgAb.


CONCLUSIONS
The FNAB-Tg achieved a sensitivity of 100% in both groups. FNAB-Tg is an easy and inexpensive technique which proved to increase the diagnostic of cytology in the early diagnosis of papillary carcinoma recurrence to CLN even in the presence of serum TgAb.
Cunha
Nuno
N
Serviço de Patologia Clínica, Instituto Português de Oncologia de Coimbra Francisco Gentil, EPE, Av. Bissaya Barreto, 98, 3000 Coimbra, Portugal. nfcunha@gmail.com
Rodrigues
Fernando
F
Curado
Fátima
F
Ilhéu
Olga
O
Cruz
Carlos
C
Naidenov
Plamen
P
Rascão
Maria João
MJ
Ganho
João
J
Gomes
Idílio
I
Pereira
Henriques
H
Real
Odete
O
Figueiredo
Paulo
P
Campos
Beatriz
B
Valido
Frederico
F
D000328:Adult; D000368:Aged; D044963:Biopsy, Fine-Needle; D002291:Carcinoma, Papillary / Q000175:diagnosis* / Q000473:pathology* / Q000601:surgery; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D066298:In Vitro Techniques; D008198:Lymph Nodes / Q000737:chemistry* / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009333:Neck; D012680:Sensitivity and Specificity; D013954:Thyroglobulin / Q000032:analysis*; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000473:pathology* / Q000601:surgery; D013965:Thyroidectomy
D013954:Thyroglobulin