The Current Role of Parathyroid Fine-Needle Biopsy (P-FNAB) with iPTH-Washout Concentration (iPTH-WC) in Primary Hyperparathyroidism: A Single Center Experience and Literature Review

Unlocking the diagnostic potential of parathormone washout: a path to accurate parathyroid tumor localization

OBJECTIVE

Accurate tumor localization is necessary for the application of minimally invasive surgery, which is preferred in the treatment of primary hyperparathyroidism. Parathormone-washout (PTH-WO) is parathyroid fine-needle aspiration followed by PTH measurement in the needle washout fluid. This study aimed to determine appropriate cutoff values for the PTH-WO method.

METHODS

A total of 402 PTH-WO assays from 339 patients were included in the study. The diagnostic accuracy of the test was assessed by accepting as a positive result a PTH-WO result higher than the serum PTH level [PTH-WO/serum PTH(PTH ratio)>1]. In addition, a cutoff value for the test was established by evaluating the PTH washout results obtained in comparison with postoperative histopathology. Undiluted test results were not included to obtain a clear numerical value in this evaluation. The results of parathyroid scintigraphy and fine needle aspiration biopsy (FNAB) were compared with postoperative histopathology.

RESULTS

While 309 (76.86%) of the PTH-WO procedures were considered positive, 93 (23.13%) were considered negative if the PTH ratio was > 1. When these results were compared with the postoperative histopathology, the test's sensitivity was 92.51%, and the specificity was 100.00%. In the analysis of the remaining 292 PTH-WO samples after excluding the undiluted ones, the sensitivity and specificity of the method were 92.3% and 94.1%, respectively, with a PTH ratio > 0.99. With a cutoff value of 99.5 ng/l for PTH-WO value, 93.1% sensitivity and 94.3% specificity were obtained. The sensitivities of parathyroid scintigraphy and FNAB were 53.4% and 15.3%, respectively.

CONCLUSIONS

The PTH-WO method is safe and cheap, with high sensitivity and specificity in localizing parathyroid tumor. In cases where radiological methods cannot achieve localization with specified cutoff values, it has high diagnostic accuracy.

Case report: Microwave ablation is a safe and effective method for primary hyperparathyroidism in pregnancy

Primary hyperparathyroidism (PHPT) is a rare disease in pregnancy and endangers the health of both pregnant women and fetuses. However, the treatments are very limited for PHPT and most of them are unsatisfactory because of the peculiar state in pregnancy. The only curable method is parathyroidectomy which can be safely performed in the second trimester of pregnancy. In this case, we reported a pregnant woman with primary parathyroid adenoma presenting hypercalcemia and severe vomit at the end of first trimester. Finally, she got cured by microwave ablation at the end of first trimester and gave birth to a healthy baby boy.

A Positive Parathyroid Washout May Obviate the Need for Nuclear Scintigraphy in Parathyroid Adenoma Localization: A Retrospective Study

BACKGROUND

Minimally invasive parathyroidectomy (MIP) in patients with a parathyroid adenoma (PA) requires imaging modalities for precise localization. Parathyroid hormone assay on ultrasound-guided fine-needle aspiration washout, or PTH washout, can be used for this purpose. It is unclear whether PTH washout complements traditional PA localization techniques such as a sestamibi (MIBI) scan or diminishes its need. This study aims to determine whether a positive PTH washout obviates the need for an MIBI scan in the preoperative localization of a PA.

METHOD

A multi-center retrospective, comparative review comprised adult patients who underwent MIP at 2 McGill University teaching hospitals between 2018 and 2022. Patients who had both PTH washout and MIBI scan for preoperative localization of PA, final histopathology reports available, and preoperative/postoperative results recorded were included in the final analysis.

RESULTS

Of the 193 patients' charts reviewed, 87 were included in this study. Of these 87 patients, 74.7% (65/87) had a positive PTH washout result. Among those, MIBI correctly detected 90.8% (59/65) of the PAs. The MIBI scan did not contribute meaningful information for any of the 65 patients who had positive PTH washout results.

CONCLUSION

These findings strongly support the use of preoperative dedicated ultrasound as the initial standard procedure. When a PA candidate on ultrasound is found, a PTH washout should be performed. If positive, it could suffice as the sole localization method for MIP surgery. When a PA was identified on ultrasound and confirmed with PTH washout, the MIBI scan did not add more information. Benefits include fewer patient tests, less exposure to ionizing radiation, and reduced healthcare expenses.

Tissue Parathyroid Hormone Washout: A Reliable Method for the Localization and Exclusion of Parathyroid Adenomas

Background and objective Accurate identification of parathyroid adenoma (PA) is essential for minimally invasive treatment of primary hyperparathyroidism (PHPT). The aim of this study is to evaluate the results of parathyroid hormone (PTH) assay in aspirates of suspicious neck lesions and to clarify its reliability in determining whether the lesion is of parathyroid origin. Methods A total of 134 lesions (104 imaging-suspected PA and 30 concomitant thyroid nodules as a control group) of 101 patients were retrospectively analyzed. Patients with positive, negative, or never scintigraphy were included in our study. Ultrasound (US) was performed again and US-guided tissue fine needle aspiration with PTH washout (PTH-WO) was performed from suspicious lesions. A PTH-WO level higher than the patient's serum PTH levels is proposed for a positive test, and a PTH-WO level lower than the upper limit of the laboratory PTH level is proposed for a negative test. A definitive diagnosis was made postoperatively histopathologically. Results PTH-WO levels (median (IQR)) were significantly higher in the positive group (n = 93, 5000 (1600) ng/L) compared to the negative group (n = 11, 17 (13.1) ng/L) and thyroid nodule aspirate group (n = 30, 14 (4.3) ng/L) (p < 0.001). Among 93 PTH-WO-positive lesions, 42 lesions (45.1%) were not identified by parathyroid scintigraphy (PS), 20 (21.5%) lesions were suspiciously PS, and 33 lesions (35.4%) were negative or suspicious by first US findings. Of the 93 patients localized with PTH-WO, two were cystic PAs ablated by aspiration. The final pathology result of 91 operated patients proved PA. The sensitivity, specificity, negative predictive value, and positive predictive value of the PTH-WO were observed as 1.00, 0.82, 0.09, and 0.91, respectively. Conclusion Comprehensive repeated US and PTH-WO from the lesion increase the accurate localization of PAs. PTH-WO is a highly reliable method for differentiating parathyroid lesions from other cervical lesions.

Clinical, Biochemical, and Sonographic Factors Influencing Performance of Parathormone Washout Measurement vs. 99mTc-MIBI Scintigraphy in the Preoperative Diagnostics of Parathyroid Adenomas

The purpose of the study was to assess the clinical, biochemical, and sonographic factors influencing the performance of parathormone washout measurement (PTHw) vs. MIBI in the preoperative localization of parathyroid adenoma (PA). The studied group consisted of 39 patients with primary or tertiary hyperparathyroidism. The measurement of PTH concentrations was performed using an electro-chemiluminescence immunoassay. Scintigraphic localization of PA was carried out using dual-tracer planar neck scintigraphy, using 74 MBq ^99mTc-pertechnetate and 740 MBq of ^99mTc-MIBI. MIBI was unambiguously positive in 74% of patients. Among patients with negative or inconclusive MIBI, 90% had a positive PTHw result. Among patients with negative PTHw, two out of three had a positive MIBI result. The PTHw of lesions <10 mm in their largest diameter yielded positive results in 95%, compared to 75% for MIBI. For lesions ≥10 mm in largest diameter, 88% were visualised using MIBI. In conclusion, PTHw is a highly effective, easy, quick, safe, and relatively cheap procedure which might be considered for PA localisation, especially in patients with lesions presenting typical ultrasound features and a size below 10 mm. MIBI remains a useful procedure in specialized centres, particularly for patients in whom PTHw failed, larger lesions, and in cases of the ectopic location of PA.

[Special features of the diagnostics and treatment of hereditary primary hyperparathyroidism]

Between 2% and 10% of patients with primary hyperparathyroidism (pHPT) are diagnosed with hereditary forms of primary hyperparathyroidism (hpHPT). They are more prevalent in younger patients before the age of 40 years, in patients with persistence or recurrence of pHPT and pHPT patients with multi-glandular disease (MGD). The various forms of hpHPT diseases can be classified into four syndromes, i.e., hpHPT associated with diseases of other organ systems, and four diseases that are confined to the parathyroid glands. Approximately 40% of patients with hpHPT suffer from multiple endocrine neoplasia type 1 (MEN-1) or show germline mutations of the MEN‑1 gene. Currently, germline mutations that lead to a specific diagnosis in patients with hpHPT have currently been described in 13 different genes, which enables a clear diagnosis of the disease; however, a clear genotype-phenotype correlation does not exist, even though the complete loss of a coded protein (e.g. due to frame-shift mutations in the calcium sensing receptor, CASR) often leads to more severe clinical consequences than merely a reduced function of the protein (e.g. due to point mutation). As the various hpHPT diseases require different treatment approaches, which do not correspond to that of sporadic pHPT, a clear definition of the specific form of hpHPT must always be strived for. Therefore, before surgery of a pHPT with clinical, imaging or biochemical suspicion of hpHPT, genetic proof or exclusion of hpHPT is necessary. The differentiated treatment approach for hpHTP can only be defined by taking the clinical and diagnostic results of all the abovenamed findings into account.

Diagnosis of parathyroid incidentaloma detected on thyroid ultrasonography: the role of fine-needle aspiration cytology and washout parathyroid hormone measurements

PURPOSE

The aim of this study was to assess the diagnostic role of fine-needle aspiration cytology (FNAC) and analyze factors associated with false-negative FNAC results in patients with parathyroid incidentaloma who were referred for ultrasonography (US)-guided fine-needle aspiration (FNA) of thyroid nodules.

METHODS

In this study, 121 patients with suspected parathyroid lesions were enrolled. The patients underwent US-guided FNAC with measurements of washout parathyroid hormone (PTH) between January 2015 and May 2020. The diagnostic performance of FNAC for the diagnosis of parathyroid lesions was assessed using surgical results and elevated washout PTH as a reference standard. The clinical and radiologic features associated with false-negative results on FNAC for the diagnosis of parathyroid lesions were evaluated.

RESULTS

Among the 121 nodules assessed, 38 were parathyroid lesions (31.4%), and 83 were non-parathyroid lesions (68.6%). The diagnostic performance of FNAC for parathyroid incidentaloma showed a sensitivity of 31.6% (12/38), specificity of 100% (83/83), positive predictive values of 100% (12/12), negative predictive values of 76.1% (83/109), and accuracy of 78.5% (95/121). The FNAC results of non-parathyroid lesions included thyroid nodules, lymph nodes, neurogenic tumors, and fat tissue. True-positive results on FNAC were significantly associated with performing FNA twice (58.3% vs. 23.1%, P=0.043).

CONCLUSION

Considering the low sensitivity of FNAC, measuring washout PTH in addition to FNAC may help accurately diagnose parathyroid incidentaloma on thyroid US. Further, the falsenegative rate for FNAC can be reduced by obtaining two or more FNA samples.

Common Carotid Artery Hematoma Following Parathyroid Adenoma FNA

We present a rare case of a common carotid artery wall hematoma after ultrasound-guided parathyroid fine-needle aspiration. The hematoma was detected within seconds from needle insertion, extending along the common carotid artery wall from the lower neck to the common carotid artery bifurcation, and it was quickly restricted with firm pressure. The patient only reported mild discomfort. A follow-up assessment by a vascular surgeon two hours later showed no signs of ischemic events and complete absorption of the hematoma without further clinical consequences. Physicians performing parathyroid fine-needle aspiration must be aware of this rare complication, which may be easily overlooked. Continuous meticulous sonographic surveillance during the fine needle aspiration procedure is the only way to directly diagnose this complication and apply immediate pressure to restrict it.