Utilidad de la detección de tiroglobulina en el aspirado de punción ganglionar cervical en el seguimiento de pacientes con cancer papilar de tiroides / Thyroglobulin levels in needle lymph node cytology for the detection of papillary thyroid cancer recurrence

Background: During the detection ofneck recurrence in patients with Papillary Thyroid Carcinoma (PTC), sometimes it is difficult to distinguish metastatic from inflammatory neck lymph nodes. The measurement of serum thyroglobulin (sTg) under thyroid hormone suppression therapy the presence of serum thyroglobulin antibodies (sAbTg), the diagnostic whole body sean and cytology can give false negative results. Measurement of thyroglobulin in the washout fluid from fine-needle aspiration biopsy (FNAB) of suspicious neck lymph nodes could improve the diagnostic aecuracy Aim: To evaluate the usefulness of detecting Tg in lymph nodes (LTg) suspicious by ultrasonography (US) and compare it to cytology. Patients and Methods: Between the years 2004 and 2007 we prospectively studied 30 patients with PTC and cervical US findings of suspicious recurrence. LTg was assayed in US guided FNAB used for cytology. Results: Sixteen out of 30 patients underwent surgery using as selective criteria an LTg higher than sTg or a positive cytology. Surgery confirmed the presence of metástasis in all 15 patients with positive LTg (8 with positive cytology) and in 1 patient with negative LTg and positive cytology (a case with undifferentiated thyroid cancer). The sensitivity was 93.7 percent for LTg and 56.2 percent for cytology. We identified byLTg 3 of 6 patients with undetectable sTg and positive sAbTg. Conclusions: The presence of LTg showed a higher sensitivity than cytology for the detection of cervical lymph node metástasis. This method is useful even in the presence ofsAbTg.

Determinación del anticuerpo antirreceptor de TSH: experiencia en pacientes con patología tiroídea y controles / Determination of TSH antireceptor antibody: experience in patients with thyroid pathology and controls

In order to measure TSH receptor antibodies (TRAb) we tried to set up a radioreceptor assay using human thyroid membranes. Due to lack of appropriate binding activity of the material obtained, we decided to use a kit which provides solubilized porcine membrane-receptors to TSH instead of human membranes, as well as calibrators that have been standarized in a receptor assay against MRC LATS std B. With these reactives we have measured TRAb in sera from 7 normal controls (C), 54 thyrotoxic patients (43 diffuse goiters [BDH], 8 multinodular goiters [BDH] and 3 subacute Thyroiditis [TSA], 3 patients with Hashimoto's Thyroiditis (TH) and 6 non-hyperthyroid Graves ophtalmopathy patients. Measurement were initially performed using calibrators and the results expressed as U/L; since a very good correlation between the expression U/L and the calculated inhibition Index (I.I.) was found (r=0.99, n=15, p<0,001), results are shown using latter. In C mean ñ SD value for I.I. was 3.4 ñ 2.37 percent so we decided to use, as cut off criteria for differentiating between normal and abnormal results, the figure 11 percent which represents the mean ñ 3 SD. According to this, 93 percent of BDH has elevated TRAb activity while only slightly more than one third of MBH had elevated values, this difference being highly significant (p<0,0001); both TSA and TH patients showed low TRAb activity while all Graves ophtalmopathy pts had elevated values, thus suggesting that they had a latent disease. We concluded that the methodology that is adequate and practical for clinical purposes. Our results show that measurement of TRAb activity is very useful in stablishing the etiology of hyperthyroidism in an individual patient. Also it provides help inthe differential diagnosis of patients with exoftalmus od unknown etiology. Its usefulness remains to be proved in the follow-up of BDH pts after been treated with antithyroid drugs