Improvement in the Detection of Cystic Metastatic Papillary Thyroid Carcinoma by Measurement of Thyroglobulin in Aspirated Fluid

Diagnostic significance of clay-like materials aspirated from thyroid nodules

Objective

The simplest way to determine the adequacy of aspirated materials is the on-site gross visual assessment of aspirated materials. However, few studies have examined the gross findings of thyroid aspirates. This study aimed to clarify the diagnostic significance of clay-like material aspirated from thyroid nodules.

Material and Methods

We reviewed 69,848 thyroid nodules that underwent aspiration cytology at Kuma Hospital between January 2007 and August 2021. Among them, 355 (0.5%) nodules with aspirated materials described as clay-like materials were retrospectively examined.

Results

Among 355 nodules, 322 (90.7%) were categorized as cystic fluid or benign. The aspirated materials were mainly composed of non-epithelial components, including colloid or proteinaceous materials, foamy histiocytes, and degenerative red blood cells. In original ultrasound reports, the incidence of intermediate and high suspicion was 11.0%. Malignant cells were observed in 21 nodules (5.9%), one-third of which were papillary thyroid carcinomas. The materials aspirated from papillary and follicular thyroid carcinomas exhibited necrotic carcinoma cells derived from infarcted areas. The overall risk of malignancy was 3.9%. The risk of malignancy in nodules interpreted as highly suspicious on ultrasound examination was 37.5%.

Conclusion

As clay-like materials aspirated from thyroid nodules were considered sufficient specimens, the recognition contributes to avoiding unnecessary second punctures. The presence of clay-like materials was indicative of the colloid and/or blood components of benign cystic lesions, or, more rarely, of infarcted carcinoma. The ultrasound examination results tended to overestimate nodules. We should reaffirm that on-site gross visual assessment of aspirated materials is a fast and reasonably accurate predictor of the on-site adequacy of the samples.

Diagnostic Efficacy of FNA-Tg in DTC Cervical LN Metastasis and its Impact Factors: A Large Retrospective Study

CONTEXT

Thyroglobulin in needle washout fluid (FNA-Tg) has the advantage of compensating for the low sensitivity of cytological analysis (FNAC) in differentiated thyroid carcinoma (DTC) lymph node (LN) metastasis. However, studies of large data sets to support this view and identify the best cutoff of FNA-Tg are lacking.

OBJECTIVE

Our study aimed to determine the best cutoff of FNA-Tg and explore the impact factors of FNA-Tg.

METHOD

A total of 1106 suspicious LNs from patients treated at West China Hospital from October 2019 to August 2021 were included. Parameters were compared between metastatic and benign LNs, and the best cutoff value of FNA-Tg was identified by ROC curves. The impact factors of FNA-Tg were analyzed.

RESULTS

In the nonsurgery group, after correcting for the effect of age and short diameter of LN, FNA-Tg was the independent risk factor for cervical LN metastasis of DTC (odds ratio [OR]: 1.048; 95% CI, 1.032-1.065). In the surgery group, after correcting for the effects of serum thyrotropin, serum Tg, long diameter of LN, and short diameter of LN, FNA-Tg was the independent risk factor for cervical LN metastasis of DTC (OR: 1.019; 95% CI, 1.006-1.033). The best cutoff value of FNA-Tg was 25.17 μg/L, and the area under the receiver operating characteristic curve, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 0.944, 0.847, 0.978, 0.982, 0.819, and 0.902, respectively. FNA-Tg highly correlated with FNA-TgAb (P < .01; Spearman correlation coefficient = 0.559), but FNA-TgAb positivity did not undermine the diagnostic efficacy of FNA-Tg for DTC LN metastasis.

CONCLUSION

The best cutoff value of FNA-Tg was 25.17 μg/L in diagnosing DTC cervical LN metastasis. FNA-Tg highly correlated with FNA-TgAb, but FNA-TgAb had no influence on the diagnostic efficacy of FNA-Tg.

Detection of thyroglobulin in fine-needle aspiration for diagnosis of metastatic lateral cervical lymph nodes in papillary thyroid carcinoma: A retrospective study

Objective

We analysed the diagnostic performance of thyroglobulin in fine-needle aspiration (FNA-Tg) in the suspicious lateral cervical lymph nodes (CLNs) in patients with papillary thyroid cancer (PTC), proposed the best cutoff value and discussed the factors that may affect the diagnostic value of FNA-Tg.

Methods

In the present study, a retrospective analysis of 403 patients with PTC with 448 suspected lateral CLNs metastasis from October 2019 to May 2021 was performed. The cutoff value according to the receiver operating characteristic (ROC) curve was determined, and the Wilcoxon rank-sum test was used to evaluate the correlation between FNA-Tg and factors.

Results

According to the ROC curve, the cutoff value of FNA-Tg was 3.69 ng/ml (sensitivity, 92.48%; specificity, 75.00%). Patients who underwent total thyroidectomy were excluded. Compared with US and FNAC, the diagnostic performance of FNA-Tg was the greatest, especially for small CLNs (diameter ≤ 1 cm), cystic CLNs, and patients with Hashimoto’s thyroiditis (HT). Moreover, FNA-Tg levels were correlated with the presence of HT (p = 0.003), the anti-thyroglobulin antibody (Tg-Ab) (p < 0.001), the ratio of metastatic lateral CLNs (p = 0.004) and Tg assay kits (p < 0.001).

Conclusions

FNA-Tg measurement is sensitive enough for diagnosing lateral CLN metastases from PTC, but its diagnostic value is compromised by a number of factors.

Thyroglobulin Measurement Through Fine-Needle Aspiration for Optimizing Neck Node Dissection in Papillary Thyroid Cancer

BACKGROUND

Thyroglobulin measurement in fine-needle aspiration (FNA-Tg) is an additional diagnostic tool of lymph node metastasis (LNM) in papillary thyroid carcinoma (PTC). However, its performance as a preoperative indicator of lateral neck LNM in PTC is unclear. We evaluated the use of FNA cytology and FNA-Tg to detect neck LNM presurgery using a simple methodology, and established a cut-off value for diagnosing LNM in PTC.

METHODS

We performed a retrospective cohort study based on hospital records, including 299 FNA-Tg measurements from 228 patients with PTC. The cut-off value for FNA-Tg was obtained through a receiver operating characteristic (ROC) curve analysis. The relationships between various parameters and FNA-Tg were analyzed using Spearman's correlation.

RESULTS

Of 299 lymph nodes (LNs) from 228 patients following surgery, 151 were malignant and 148 were benign. The median FNA-Tg levels were 414.40 ng/mL and 6.36 ng/mL in the metastatic and benign LNs, respectively. An FNA-Tg cut-off value of 28.3 ng/mL had the best diagnostic performance (93.38% sensitivity, 70.27% specificity, area under the ROC curve [AUC] 0.868) in the whole cohort. The diagnostic value performed better in the lateral neck group (level II-V, n = 163) than in the central neck group (level VI, n = 136); in the lateral neck group, the sensitivity and specificity of the FNA-Tg cut-off (16.8 ng/mL) were 96.25% and 96.36%, respectively.

CONCLUSIONS

FNA-Tg is a useful technique for the diagnosis of LNM before surgery, especially in lateral neck dissection.

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR1900028547.