Preoperative Localization for Primary Hyperparathyroidism: A Clinical Review

Primary hyperparathyroidism: predictors of sporadic multi-gland disease

In this review, we discuss the definition, prevalence, and etiology of sporadic multiglandular disease (MGD), with an emphasis on its preoperative and intraoperative predictors. Primary hyperparathyroidism (PHPT) is the third-most common endocrine disorder, and multiglandular parathyroid disease (MGD) is a cause of PHPT. Hereditary MGD can be definitively diagnosed with detailed family history and genetic testing, whereas sporadic MGD presents a greater challenge in clinical practice, and parathyroidectomy for MGD is associated with a higher risk of surgical failure than single gland disease (SGD). Therefore, it is crucial to be able to predict the presence of sporadic MGD in a timely manner, either preoperatively or intraoperatively. Various predictive methods cannot accurately identify all cases of sporadic MGD, but they can greatly optimize the management of MGD diagnosis and treatment and optimize the cure rate. Future research will urge us to investigate more integrative predictive models as well as increase our understanding of MGD pathogenesis.

Characteristics, management and outcomes of primary hyperparathyroidism from 2009 to 2021: a single centre report from South Africa

BACKGROUND

There has been a notable shift towards the diagnosis of less severe and asymptomatic primary hyperparathyroidism (PHPT) in developed countries. However, there is a paucity of recent data from sub-Saharan Africa (SSA), and also, no reported data from SSA on the utility of intra-operative parathyroid hormone (IO-PTH) monitoring. In an earlier study from Inkosi Albert Luthuli Central Hospital (IALCH), Durban, South Africa (2003-2009), majority of patients (92.9%) had symptomatic disease. The aim of this study was to evaluate the clinical profile and management outcomes of patients presenting with PHPT at IALCH.

METHODS

A retrospective chart review of patients with PHPT attending the Endocrinology clinic at IALCH between July 2009 and December 2021. Clinical presentation, laboratory results, radiologic findings, surgical notes and histology were recorded.

RESULTS

Analysis included 110 patients (87% female) with PHPT. Median age at presentation was 57 (44; 67.5) years. Symptomatic disease was present in 62.7% (n:69); 20.9% (n:23) had a history of nephrolithiasis and 7.3% (n:8) presented with previous fragility fractures. Mean serum calcium was 2.87 ± 0.34 mmol/l; median serum-PTH was 23.3 (15.59; 45.38) pmol/l, alkaline phosphatase 117.5 (89; 145.5) U/l and 25-hydroxyvitamin-D 42.9 (33.26; 62.92) nmol/l. Sestamibi scan (n:106 patients) identified an adenoma in 83.02%. Parathyroidectomy was performed on 84 patients with a cure rate of 95.2%. Reasons for conservative management (n:26) included: no current surgical indication (n:7), refusal (n:5) or deferral of surgery (n:5), loss to follow-up (n:5) and assessed as high anaesthetic risk (n:4). IO-PTH measurements performed on 28 patients indicated surgical success in 100%, based on Miami criteria. Histology confirmed adenoma in 88.1%, hyperplasia in 7.1% and carcinoma in 4.8%. Post-operative hypocalcaemia developed in 30 patients (35.7%), of whom, 14 developed hungry bone syndrome (HBS). In multivariate analysis, significant risk factors associated with HBS included male sex (OR 7.01; 95% CI 1.28, 38.39; p 0.025) and elevated pre-operative PTH (OR 1.01; 95% CI 1.00, 1.02; p 0.008).

CONCLUSIONS

The proportion of asymptomatic PHPT has increased at this centre over the past decade but symptomatic disease remains the dominant presentation. Parathyroidectomy is curative in the majority of patients. IO-PTH monitoring is valuable in ensuring successful surgery.

Comparing accuracy of machine learning approaches to identifying parathyroid adenomas: Lessons and new directions

PURPOSE

The purpose of this investigation is to understand the accuracy of machine learning techniques to detect biopsy-proven adenomas from similar appearing lymph nodes and factors that influence accuracy by comparing support vector machine (SVM) and bidirectional Long short-term memory (Bi-LSTM) analyses. This will provide greater insight into how these tools could integrate multidimensional data and aid the detection of parathyroid adenomas consistently and accurately.

METHODS

Ninety-nine patients were identified; 93 4D-CTs of patients with pathology-proven parathyroid adenomas were reviewed; 94 parathyroid adenomas and 112 lymph nodes were analyzed. A 2D slice through the lesions in each phase was used to perform sequence classification with ResNet50 as the pre-trained network to construct the Bi-LSTM model, and the mean enhancement curves were used to form an SVM model. The model characteristics and accuracy were calculated for the training and validation data sets.

RESULTS

On the training data, the area under the curve (AUC) of the Bi-LSTM was 0.99, while the SVM was 0.95 and statistically significant on the DeLong test. The overall accuracy of the Bi-LSTM on the validation data set was 92 %, while the SVM was 88 %. The accuracy for parathyroid adenomas specifically was 93 % for the Bi-LSTM and 83 % for the SVM model.

CONCLUSION

Enhancement characteristics are a distinguishing feature that accurately identifies parathyroid adenomas alone. The Bi-LSTM performs statistically better in identifying parathyroid adenomas than the SVM analysis when using both morphologic and enhancement information to distinguish between parathyroid adenomas and lymph nodes.

SUMMARY STATEMENT

The Bi-LSTM more accurately identifies parathyroid adenomas than the SVM analysis, which uses both morphologic and enhancement information to distinguish between parathyroid adenomas and lymph nodes, performs statistically better.

Ultrasound characteristics of normal parathyroid glands and analysis of the factors affecting their display

BACKGROUND

Parathyroid glands are important endocrine glands, and the identification of normal parathyroid glands is crucial for their protection. The aim of this study is to explore the sonographic characteristics of normal parathyroid glands and analyze the factors affecting their display.

METHODS

Seven hundred three subjects who underwent physical examination at our hospital were included. The number, location, size, morphology, echogenicity and blood flow distribution of parathyroid glands were recorded. The ultrasound characteristics and display rate were also summarized. Meanwhile, shear wave elastography was performed in 50 cases to provide the stiffness measurements, and 26 cases received contrast-enhanced ultrasonography for the assessment of microcirculatory perfusion. Furthermore, we analyzed the factors affecting parathyroid display, including basic information of the subjects and ultrasound features of the thyroid.

RESULTS

① A total of 1038 parathyroid glands were detected, among which, 79.29% were hyperechoic, 20.71% were isoechoic, 88.15% were oval-shaped, and 86.71% had blood flow of grade 0-I. ② 81.79% of the subjects had at least one parathyroid gland detected. ③ The Emean, Emax, PI and AUC of the parathyroid glands were significantly lower than those of the adjacent thyroid tissue (P < 0.05). ④ The display of normal parathyroid glands was related to BMI, thyroid echogenicity and thyroid volume of the subjects (P < 0.05).

CONCLUSIONS

Normal parathyroid glands tend to appear as oval-shaped hyperechoic nodules with blood flow of grade 0-I. BMI, thyroid echogenicity and thyroid volume are independent factors affecting the display of parathyroid glands.

Continuous innovation in precision radio-guided surgery

Since its origins, nuclear medicine has faced technological changes that led to modifying operating modes and adapting protocols. In the field of radioguided surgery, the incorporation of preoperative scintigraphic imaging and intraoperative detection with the gamma probe provided a definitive boost to sentinel lymph node biopsy to become a standard procedure for melanoma and breast cancer. The various technological innovations and consequent adaptation of protocols come together in the coexistence of the disruptive and the gradual. As obvious examples we have the introduction of SPECT/CT in the preoperative field and Drop-in probes in the intraoperative field. Other innovative aspects with possible application in radio-guided surgery are based on the application of artificial intelligence, navigation and telecare.

Preoperative identification of small parathyroid adenomas-better done by fluorocholine positron emission tomography/computed tomography

Background

Preoperative localization imaging studies are crucial for safe and successful parathyroidectomy in patients with primary hyperparathyroidism (pHPT), especially in focused approaches. A common imaging sequence is ultrasound followed by scintigraphy. These techniques, but not 18F-fluorocholine positron emission tomography/computed tomography (PET/CT), show lower detection rates in multiglandular disease (MGD), which is associated with smaller adenomas. In this study, we evaluate the accuracy of these modalities in small parathyroid adenomas (PAs) and discuss the potential sequence of preoperative localization diagnostics.

Methods

Patients undergoing parathyroidectomy for pHPT were retrospectively categorized into small adenoma (specimen diameter <10 mm) and large adenoma. The groups were compared for accuracy of preoperative imaging studies, short-term and long-term outcomes.

Results

Among 147 patients retrospectively analyzed in this study, 38 small PAs were found. Preoperative correct quadrant prediction for small adenomas was significantly lower for ultrasound (P=0.03) and single-photon emission computed tomography/CT (SPECT/CT) (P<0.01) but not for choline PET/CT. While PET/CT was performed significantly more often in small PAs (P<0.01), it showed highly significant superiority over the other imaging modalities in accurate preoperative localization in both small (P<0.0001) and large PAs (P<0.01). There was no difference in calcium and parathyroid hormone (PTH) levels at latest follow-up with slightly more recurrences in small adenomas (P=0.08).

Conclusions

Choline PET/CT showed a better diagnostic yield especially for small and multiple adenomas and was better in prediction of the correct localization. It could therefore serve as a second-line imaging modality.

Diagnostic Performance of Magnetic Resonance Imaging for Parathyroid Localization of Primary Hyperparathyroidism: A Systematic Review

Accurate preoperative localization is crucial for successful minimally invasive parathyroidectomy in primary hyperparathyroidism (PHPT). Preoperative localization can be challenging in patients with recurrent and/or multigland disease (MGD). This has led clinicians to investigate multiple imaging techniques, most of which are associated with radiation exposure. Magnetic resonance imaging (MRI) offers ionizing radiation-free and accurate imaging, making it an attractive alternative imaging modality. The objective of this systematic review is to provide an overview of the diagnostic performance of MRI in the localization of PHPT. PubMed and Embase libraries were searched from 1 January 2000 to 31 March 2023. Studies were included that investigated MRI techniques for the localization of PHPT. The exclusion criteria were (1) secondary/tertiary hyperparathyroidism, (2) studies that provided no diagnostic performance values, (3) studies published before 2000, and (4) studies using 0.5 Tesla MRI scanners. Twenty-four articles were included in the systematic review, with a total of 1127 patients with PHPT. In 14 studies investigating conventional MRI for PHPT localization, sensitivities varied between 39.1% and 94.3%. When employing more advanced MRI protocols like 4D MRI for PHPT localization in 11 studies, sensitivities ranged from 55.6% to 100%. The combination of MR imaging with functional techniques such as 18F-FCH-PET/MRI yielded the highest diagnostic accuracy, with sensitivities ranging from 84.2% to 100% in five studies. Despite the limitations of the available evidence, the results of this review indicate that the combination of MR imaging with functional imaging techniques such as 18F-FCH-PET/MRI yielded the highest diagnostic accuracy. Further research on emerging MR imaging modalities, such as 4D MRI and PET/MRI, is warranted, as MRI exposes patients to minimal or no ionizing radiation compared to other imaging modalities.

The Utility of 4D-CT Imaging in Primary Hyperparathyroidism Management in a Low-Volume Center

Background: Ultrasonography (US) and the 99mTc-sestamibi parathyroid scan (SPS) may have suboptimal accuracy when detecting the localization of enlarged parathyroid gland(s) (PTG). Therefore, the more accurate four-dimensional computed tomography scan (4D-CT) has been employed for PTG imaging. Currently, there is a paucity of data evaluating the utility of 4D-CT in low caseload settings. Aim and Objectives: To evaluate the impact of PTG imaging, using 4D-CT in conjunction with its intraoperatively displayed results, on the outcomes of surgical PTX. Materials and Methods: A single-center retrospective analysis of surgically treated patients with pHPT from 01/2010 to 01/2021 was conducted. An evaluation of the impact of the preoperative imaging modalities on the results of surgical treatment was carried out. Results: During the study period, 290 PTX were performed; 45 cases were excluded due to surgery for secondary, tertiary or recurrent HPT, or due to the use of alternative imaging techniques. The remaining 245 patients were included in the study. US was carried out for PTG imaging in 236 (96.3%), SPS in 93 (38.0%), and 4D-CT in 52 patients (21.2%). The use of 4D-CT was associated with a significantly higher rate of successful localization of enlarged PTG (49 cases, 94.2%) compared to US and SPS (74 cases, 31.4%, and 54 cases, 58.1%, respectively). We distinguished between three groups of patients based on preoperative imaging: (1) PTG lateralization via US or SPS in 106 (43.3%) cases; (2) precise localization of PTG via 4D-CT in 49 (20.0%) patients; and (3) in 90 cases (36.7%), PTG imaging failed to localize an enlarged gland. The group of 4D-CT localization had significantly shorter operative time, lower rate of simultaneous thyroid resections, as well as lower rate of removal of ≥2 PTG, compared to the other groups. The 4D-CT imaging was also associated with the lowest perioperative morbidity and with the lowest median PTH in the one month follow-up; however, compared to the other groups, these differences were statistically not significant. The implementation of 4D-CT (since 01/2018) was associated with a decrease in the need for redo surgery (from 11.5% to 7.3%) and significantly increased the annual case load of PTX at our institution (from 15.3 to 41.0) compared to the period before 4D-CT diagnostics. Conclusions: 4D-CT imaging enabled to precisely locate almost 95% of enlarged PTG in patients with pHPT. Accurate localization and intraoperatively displayed imaging results are useful guides for surgeons to make PTX a faster and safer procedure in a low-volume center.

Efficacy of surgeon-performed, intra-operative ultrasound scan for localisation of parathyroid adenomas in patients with primary hyperparathyroidism

BACKGROUND

In the UK, guidance recommends ultrasound scanning alone or in combination with sestamibi scintigraphy to guide surgery in patients with primary hyperparathyroidism. If an adenoma is localised on imaging, this can facilitate targeted or minimally invasive surgery. Surgeon-performed ultrasound scan on the operating table benefits from being performed on an anaesthetised patient with optimal positioning. The aim of this study was to investigate the efficacy of intra-operative, blinded, surgeon-performed ultrasound scan in localisation of parathyroid adenomas.

METHODS

Prospective data were collected on consecutive patients undergoing surgery for primary hyperparathyroidism at a single tertiary centre from November 2019 to June 2021. Patients underwent blinded, surgeon-performed ultrasound scan under general anaesthesia immediately prior to surgery. Localisation results from pre-operative imaging and surgeon-performed ultrasound scan were then compared with the intra-operative findings.

RESULTS

Forty-nine patients underwent surgery and were found to have single-gland disease. Sestamibi scintigraphy, radiologist-performed ultrasound scan and surgeon-performed ultrasound scan had sensitivities of 59.4, 43.75 and 73.8 per cent, respectively. Surgeon-performed ultrasound scan had a statistically significantly increased sensitivity compared with radiologist-performed ultrasound (p < 0.05).

CONCLUSION

Intra-operative, surgeon-performed ultrasound scan is effective in localising parathyroid adenomas and may be a useful adjunct to facilitate minimally invasive parathyroid surgery.

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.

Multi-modality parathyroid imaging: A shifting paradigm

The goal of parathyroid imaging in hyperparathyroidism is not diagnosis, rather it is the localization of the cause of hyperparathyroidism for planning the best therapeutic approach. Hence, the role of imaging to accurately and precisely localize the abnormal parathyroid tissue is more important than ever to facilitate minimally invasive parathyroidectomy over bilateral neck exploration. The common causes include solitary parathyroid adenoma, multiple parathyroid adenomas, parathyroid hyperplasia and parathyroid carcinoma. It is highly imperative for the radiologist to be cautious of the mimics of parathyroid lesions like thyroid nodules and lymph nodes and be able to differentiate them on imaging. The various imaging modalities available include high resolution ultrasound of the neck, nuclear imaging studies, four-dimensional computed tomography (4D CT) and magnetic resonance imaging. Contrast enhanced ultrasound is a novel technique which has been recently added to the armamentarium to differentiate between parathyroid adenomas and its mimics. Through this review article we wish to review the imaging features of parathyroid lesions on various imaging modalities and present an algorithm to guide their radiological differentiation from mimics.

Localization Strategy Prior to Radiofrequency Ablation for Primary and Secondary Hyperparathyroidism

Objective: Preoperative localization in patients with primary or secondary hyperparathyroidism before radiofrequency ablation (RFA) is crucial. There is currently a lack of consensus regarding imaging protocol. Evaluating the diagnostic performance of ultrasound, four-dimensional computed tomography (4D-CT), and technetium 99m-sestamibi single-photon-emission-computed tomography/computed tomography (SPECT/CT) is necessary for RFA of hyperparathyroidism. Methods: This retrospective study recruited patients with primary or secondary hyperparathyroidism who underwent ultrasound, 4D-CT, and SPECT/CT before RFA at a single institution. The sensitivity, accuracy, and receiver operating characteristic curve analysis were used to evaluate the diagnostic performance of the imaging modalities. Results: A total of 33 patients underwent RFA for hyperparathyroidism (8 patients with primary hyperparathyroidism, 25 patients with secondary hyperparathyroidism). Ultrasound had the highest sensitivity (0.953) and accuracy (0.943), while 4D-CT had higher sensitivity and accuracy than SPECT/CT (sensitivity/accuracy, 4D-CT vs. SPECT/CT: 0.929/0.920 vs. 0.741/0.716). Combined ultrasound with 4D-CT and the three combined modalities achieved equivalent, and the highest, diagnostic performance (sensitivity 1.000, accuracy 0.989). The lesion length and volume were important predictors of the diagnostic performance of 4D-CT and SPECT/CT (area under curve of length in 4D-CT/volume in 4D-CT/length in SPECT/volume in SPECT: 0.895/0.834/0.767/0.761). Conclusion: Combined ultrasound with 4D-CT provides optimal preoperative localization prior to RFA in patients with primary or secondary hyperparathyroidism. The length and volume of parathyroid lesions are determinative of the diagnostic performance of 4D-CT and SPECT/CT.

Parathyroidectomy for primary hyperparathyroidism: A retrospective analysis of localization, surgical characteristics, and treatment outcomes

OBJECTIVE

To evaluate parathyroidectomy for primary hyperparathyroidism (PHPT) regarding localization, surgical characteristics, and treatment outcomes.

METHODS

Seventy-eight patients who underwent parathyroidectomy for PHPT were retrospectively reviewed. The results were analyzed according to intraoperative localization technique (IOLT), intraoperative parathyroid hormone (IOPTH) monitoring, and intraoperative nerve monitoring (IONM). The localization accuracy of ultrasonography (US), computed tomography (CT), and single-photon emission computed tomography (SPECT)-CT with sestamibi Tc99m was evaluated.

RESULTS

Parathyroidectomy was successfully completed in all 78 patients, achieving 100% surgical cure. For 60 patients with IOPTH monitoring, 10-min IOPTH decreased >50% from baseline in 57 (95.0%), and they achieved surgical cure. In the remaining three (5.0%) patients with ≤50% decrease in 10-min IOPTH, 20-min IOPTH decreased >50% from baseline in two (3.3%) patients, achieving surgical cure without additional neck exploration. There were no differences in surgical cure and complications as a function of IOLT use or IOPTH monitoring. Operating time was significantly shorter with IOLT and IOPTH monitoring than without (IOLT: 70.9 min vs. 88.0 min, p = 0.013; IOPTH: 74.9 min vs. 91.9 min, p = 0.037). All 78 patients had adenoma including one patient with a double adenoma. Vocal cord paralysis was not observed in our series, regardless of IONM. US, CT, and SPECT-CT localized the pathological parathyroid gland accurately in 88.1%, 85.5%, and 86.8% of patients, respectively (p = 0.894).

CONCLUSION

The surgical outcomes of parathyroidectomy for PHPT were excellent regardless of IOLT and IOPTH monitoring. However, these techniques can maximize the performance of parathyroid surgery by reducing operating time and rescuing challenging cases.

Evolving Role of [18F]Flurocholine PET/CT in Assessing Primary Hyperparathyroidism: Can It Be Considered the First-Line Functional Imaging Approach?

The accurate detection of hyperfunctioning parathyroid tissue (HFPT) is pivotal in the preoperative assessment of primary hyperparathyroidism (PHPT). PET/CT using [¹⁸F]fluorocholine ([¹⁸F]FCH) showed superior diagnostic performance compared to conventional functional imaging modalities. We aimed to evaluate the diagnostic performance of [¹⁸F]FCH PET/CT as a first-line functional imaging approach in patients with clinically diagnosed PHPT. The imaging and clinical data of 321 PHPT patients, including 271 overt PHPT and 50 mild PHPT, who underwent [¹⁸F]FCH PET/CT as first-line imaging were analysed in this retrospective study. Histopathology was the reference standard. In case of no available histopathology evaluation (conservative management), imaging and clinical follow-ups were considered reference standards. In the overt group (n = 271), [¹⁸F]FCH PET/CT showed sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of 0.99, 0.91, 1.00, 0.80, and 0.99, respectively. Regarding the correlation of the index lesions and initial laboratory data, all [¹⁸F]FCH PET/CT parameters (SUVs, SULs, and mSAD) were significantly correlated with the serum iPTH level. Additionally, SUVmax, SULpeak, and mSAD were significantly associated with the serum calcium level. In the mild group (n = 50), [¹⁸F]FCH PET/CT showed a sensitivity, specificity, PPV, NPV, and accuracy of 0.93, 0.75, 0.95, 0.67, and 0.90. In conclusion, [¹⁸F]FCH PET/CT revealed high diagnostic performance in the detection of HFPTs and the potential to be considered as a first-line imaging modality in the assessment of PHPT, including both overt and mild types. However, its cost-benefit concerning the clinical impact of early PHPT detection should be investigated in future studies.

Follicular Neoplasm of Thyroid Revisited: Current Differential Diagnosis and the Impact of Molecular Testing

The diagnosis of "follicular neoplasm" (FN) in thyroid cytopathology has a long history that originated not long after the practice of fine-needle aspiration (FNA) of thyroid nodules. From the outset, this interpretive category was intended to convey a set of differential diagnoses rather than a precise diagnosis, as key diagnostic features, such as capsular and vascular invasion, were not detectable on cytology preparations. Cytologic-histologic correlation studies over the past several decades have shown that FN interpretation can be applied to the spectrum of nonneoplastic tumors to carcinomas. Most tumors classified as FN include follicular adenoma, follicular carcinoma, noninvasive follicular thyroid tumor with papillary-like nuclear features, and follicular variant of papillary thyroid carcinoma. Less common entities that may be classified as FN on FNA include hyalinizing trabecular tumor (HTT), poorly differentiated thyroid carcinoma, medullary carcinoma, and nonthyroidal lesions such as parathyroid tissue, paraganglioma, and metastatic tumors. Advances in our ability to detect characteristic molecular alterations (eg, GLIS gene rearrangements for hyalinizing trabecular tumor) in FNA samples may assist in the identification of some of these entities. In this review, we summarize the pathophysiology, history, and evolution of the terminology and the current differential diagnosis according to the recently published 2022 World Health Organization classification, molecular testing, and management of nodules classified as FN.

Usefulness of PET/CT with Carbon-11-Labeled Methionine in the Diagnosis of Tertiary Hyperparathyroidism

Introduction: Tertiary hyperparathyroidism (tHP) may develop in patients treated with hemodialysis or peritoneal dialysis. Parathyroidectomy may result in a significant reduction in the severity of symptoms. For the effective surgical treatment of hyperparathyroidism, proper localization of the parathyroid glands prior to surgery is essential. The sensitivity of scintigraphy in the diagnosis of tHP is lower than in the diagnosis of primary hyperparathyroidism. In recent years, positron emission tomography (PET/CT) has been gaining importance, usually as a complementary technique. Aim: The aim of this study was to determine the usefulness of PET/CT with [11C]MET in the preoperative localization diagnosis of patients with tertiary hyperparathyroidism caused by chronic kidney disease, in whom first-line diagnostic methods did not allow the localization of pathologically parathyroid glands. Material and methods: The study was conducted in a group of 19 adult patients with severe tHP who were resistant or intolerant to non-invasive treatment, with negative results of scintigraphy and ultrasonography of the neck. The study protocol included measurement of the concentration of calcium, phosphorus, and PTH in the blood serum and performing PET/CT with [11C]MET. Results: A positive result of PET/CT was obtained in 89.5% of the patients (17/19). Parathyroidectomy was performed in 52.9% of the patients (9/17) with positive results of PET/CT with [11C]MET, which were fully consistent with the results of the histopathological examinations of the removed parathyroid glands. On this basis, the sensitivity of PET/CT with [11C]MET in the preoperative localization diagnosis of patients with tHP was found to be 100%. Multiple lesions were visualized in 57.9% of the patients (11/19). Ectopic lesions were visualized in 21.1% of the patients (4/19). Conclusions: PET/CT with [11C]MET is a sensitive technique for the second-line preoperative imaging of parathyroid glands in patients with tertiary hyperparathyroidism in whom first-line examinations, such as ultrasound and scintigraphy, has failed.

Approach to the patient: Management of parathyroid diseases across pregnancy

Taking care of patients with parathyroid disorders during pregnancy requires consideration of the physiological fundamental changes in bone and mineral metabolism occurring in these women. Diagnostic and therapeutic procedures regarding primary hyperparathyroidism (PHPT) and hypoparathyroidism significantly differ from the non-pregnant population. PHPT should preferably be cured by parathyroidectomy before pregnancy as in women with hypercalcemic PHPT, maternal and fetal pregnancy complications seem to increase according to the degree of hypercalcemia. Parathyroidectomy, if needed during pregnancy, is preferentially performed in the second trimester. Conservative treatment is recommended for milder cases and is mainly restricted to hydration with only limited evidence regarding drug treatment. Women with hypoparathyroidism can be informed that there are no major concerns regarding disease associated infertility and that the risk of pregnancy complications is low if the disease is properly managed. Regular active surveillance is recommended as requirements for calcium and active vitamin D may change during the course of pregnancy in either direction, with an overall trend for rather reduced doses. Any woman suffering from parathyroid disorders during pregnancy requires further surveillance in the postpartum period and during lactation, as there is an increased risk of hypercalcemia after delivery. Newborns of mothers with parathyroid diseases should, depending on disease severity, be carefully monitored for calcium levels in the first days (to weeks) after delivery as intrauterine exposure to hyper- or hypocalcemia may impact their postnatal regulation of calcium metabolism.

Parathyroid adenoma presenting as chronic pancreatitis: A case report and literature review

BACKGROUND

Most patients with parathyroid adenomas are asymptomatic and rarely present with chronic pancreatitis (CP). Several studies have reported a positive association between primary hyperparathyroidism (PHPT) and pancreatitis. Parathyroidectomy is the definitive treatment for PHPT. IV bisphosphonates can be considered the drug of choice for bridge to surgery.

METHODS

We reported a 57-year-old female patient was admitted to the emergency room with left upper quadrant abdominal pain and a diagnosis of recurrent pancreatitis. Magnetic Resonance Cholangiopancreatography confirmed the diagnosis of CP. The patient had no common etiology of pancreatitis. Persistent hypercalcemia was noted despite administering intravenous fluids, and Calcitonin. Intravenous Pamidronate, a Bisphosphonate derivative, was also administered. Although calcium levels initially decreased, they were later found to rebound to previous levels.

RESULTS

A diagnosis of parathyroid adenoma and PHPT was made based on the elevated parathyroid hormone levels and cervical ultrasonography indicated right inferior parathyroid adenoma. Technetium-99m methoxy-isobutyl-isonitrile scintigraphy revealed a focal hot spot of tracer accumulation at the right lower thyroid bed. The patient underwent right lower parathyroidectomy smoothly and successfully. After right lower parathyroidectomy, she had normal serum calcium levels (9.2 mg/dL) and parathyroid hormone (16.1 pg/mL). There was no recurrent abdominal pain after the operation.

CONCLUSION

CP is a rare manifestation of parathyroid adenoma. When patients with a history of recurrent pancreatitis, without common causes of pancreatitis, present persistent elevated serum calcium levels, PHPT could be suspected.

Persistence of primary hyperparathyroidism: a single-center experience

BACKGROUND

Parathyroidectomy is the only definitive treatment for primary hyperparathyroidism (PHPT). Precise localization of abnormal glands is a key to a successful surgery. Most patients are expected to be successfully treated with focused parathyroidectomy. However, this approach is associated with a risk of existing multiglandular disease which may lead to the postoperative persistence of PHPT.

METHODS

Eight hundred ten patients who underwent an initial surgery for PHPT at SPBU Hospital in 2017-2018 were included in the study. Preoperative imaging results were evaluated. Multivariate logistic regressions were calculated to estimate predictive values of preoperative data for the risk of postoperative persistence and risk of MGD.

RESULTS

Multiglandular disease was found to be a leading cause of persistent hyperparathyroidism. An anamnesis of thyroid surgery was found to be a significant risk factor for the persistence of hyperparathyroidism. The rate of persistence did not differ significantly between groups with bilateral neck exploration and focused parathyroidectomy. Age, sex, body mass index as well as negative results of preoperative US, MIBI, and 4D CT were not independently associated with a higher risk of MGD. All preoperative imaging modalities showed from low to moderate sensitivity for the detection of MGD. The frequency of cases of a missed second adenoma did not differ significantly between patients with concordant and discordant preoperative data. There were 7 cases with previously unsuspected second adenomas found solely due to bilateral neck exploration.

CONCLUSIONS

None of the combination of preoperative visualization modalities was able to rule out the MGD and reliably identify patients for focused parathyroidectomy. Additional preoperative visualization failed to improve overall results. Bilateral neck exploration appeared to have a slight benefit for the patients with concordant preoperative imaging results.

Update on Preoperative Parathyroid Localization in Primary Hyperparathyroidism

Parathyroidectomy is the treatment of choice for primary hyperparathyroidism when the clinical criteria are met. Although bilateral neck exploration is traditionally the standard method for surgery, minimally invasive parathyroidectomy (MIP), or focused parathyroidectomy, has been widely accepted with comparable curative outcomes. For successful MIP, accurate preoperative localization of parathyroid lesions is essential. However, no consensus exists on the optimal approach for localization. Currently, ultrasonography and technetium-99m-sestamibi-single photon emission computed tomography/computed tomography are widely accepted in most cases. However, exact localization cannot always be achieved, especially in cases with multiglandular disease, ectopic glands, recurrent disease, and normocalcemic primary hyperparathyroidism. Therefore, new modalities for preoperative localization have been developed and evaluated. Positron emission tomography/computed tomography and parathyroid venous sampling have demonstrated improvements in sensitivity and accuracy. Both anatomical and functional information can be obtained by combining these methods. As each approach has its advantages and disadvantages, the localization study should be deliberately chosen based on each patient's clinical profile, costs, radiation exposure, and the availability of experienced experts. In this review, we summarize various methods for the localization of hyperfunctioning parathyroid tissues in primary hyperparathyroidism.

[Role of preoperative visualization in the choice of surgery for primary hyperparathyroidism]

BACKGROUND

Precise localization of abnormal parathyroid glands is important for a successful surgery for primary hyperparathyroidism (PHPT). While a large number of patients can be successfully treated with the focused parathyroidectomy, there is a considerable rate of the persistent PHPT mostly because of undetected multiglandular disease (MGD).

AIM

The aim of the study was to evaluate the meaning of preoperative visualization data for planning the surgery for patients with PHPT.

MATERIALS AND METHODS

The study was conducted at SPBU Hospital in 2017-2018. 810 patients who underwent a primary surgery for PHPT were included in the study. Preoperative imaging results were investigated and multivariative logistic regressions were calculated to assess the predictive values of preoperative data. The rate of cases with persistent disease and cases with MGD were compared between patients with different results of preoperative data.

RESULTS

Age, sex, body mass index, negative results of preoperative US, MIBI and 4D CT were not independently associated with the higher risk of multiglandular disease. The larger number of performed preoperative visualization studies were associated with the higher risk of persistence. 37% cases of MGD were not identified preoperatively. There were 7 cases with previously unsuspected second adenomas found only due to bilateral neck exploration.

CONCLUSION

Any combination of preoperative visualization modalities was not able to rule out the MGD reliably. Efficacy of surgical treatment was not associated with the higher number of preoperative studies. Bilateral neck exploration may decrease the rate of the persistent hyperparathyroidism improving the identification of multiglandular disease.

Percentage arterial enhancement on 2D CT in the diagnosis of primary hyperparathyroidism: A prospective validation study and potential pitfalls

BACKGROUND

Parathyroid lesions are identified by subjective enhancement and washout patterns on computed tomography (CT). We have previously proposed "percentage arterial enhancement" (PAE) as an objective index and now aim to validate its performance prospectively.

METHODS

Dual-phase CT was performed in 40 consecutive primary hyperparathyroidism patients. PAE was calculated as [{arterial phase Hounsfield unit (HU)-unenhanced phase HU}/unenhanced phase HU] × 100. PAE > 128.9% was considered parathyroid.

RESULTS

PAE had 94.2% sensitivity, 100% positive predictive value (PPV) in lateralization, and sensitivity and PPV of 93.9% in quadrant localization of single-gland disease. PAE failed to identify two lesions: an intrathyroidal parathyroid carcinoma in the background of multinodular goiter and another lower enhancing cystic parathyroid adenoma. PAE had 60% sensitivity, and 100% PPV to identify multigland disease. The mean effective dose was 2.74 mSV.

CONCLUSIONS

PAE is a specific CT index for parathyroid lesions with less radiation exposure. Areas of caution include intrathyroidal and cystic lesions.

Management and Long-Term Follow-Up of Hyperparathyroidism in Multiple Endocrine Neoplasia Type 1: Single Center Experience

Background: Primary hyperparathyroidism (PHPT) in the most common and earliest manifestation of multiple endocrine neoplasia type-1 (MEN1). Epidemiological data have been reported in MEN1 patients but data on long-term follow-up focusing on PHPT are scarce. Methods: In this retrospective cohort study, we included patients diagnosed with MEN1-related PHPT that were under regular follow-up in our institution. Results: Data on 68 patients (39 males), with a mean age at MEN1-diagnosis of 39 ± 13.06 years, were analyzed. Pancreatic neuroendocrine tumors were encountered in 82% (71% nonsecreting) followed by pituitary adenomas in 66% (49% nonsecreting). Mean age at PHPT diagnosis was 35.2 ± 4.0 years. Parathyroidectomy was performed in 57 patients (82.3%), of whom 56% achieved long-term remission, while 12.2% and 31.5% had persistent and recurrent disease, respectively (median follow-up of 4 years; range 1–21 years). Cinacalcet restored serum calcium levels in 33.8%, both as first and as a second line treatment. Permanent hypoparathyroidism occurred in 19.2%. MEN1 pathogenic variants were identified in 77.2% of the tested individuals, but no genotype-phenotype associations were reported. Conclusions: MEN1-related PHPT involves a multiglandular disease and its management remains a therapeutic challenge, as recurrent disease can develop even after 20 years of follow-up. Prolonged follow-up of these patients at referral centers is critical for their optimal management.

European Expert Consensus on Practical Management of Specific Aspects of Parathyroid Disorders in Adults and in Pregnancy: Recommendations of the ESE Educational Program of Parathyroid Disorders

This European expert consensus statement provides recommendations for the diagnosis and management of primary hyperparathyroidism (PHPT), chronic hypoparathyroidism in adults (HypoPT), and parathyroid disorders in relation to pregnancy and lactation. Specified areas of interest and unmet needs identified by experts at the second ESE Educational Program of Parathyroid Disorders (PARAT) in 2019, were discussed during two virtual workshops in 2021, and subsequently developed by working groups with interest in the specified areas. PHPT is a common endocrine disease. However, its differential diagnosing to familial hypocalciuric hypercalcemia (FHH), the definition and clinical course of normocalcemic PHPT, and the optimal management of its recurrence after surgery represent areas of uncertainty requiring clarifications. HypoPT is an orphan disease characterized by low calcium concentrations due to insufficient PTH secretion, most often secondary to neck surgery. Prevention and prediction of surgical injury to the parathyroid glands are essential to limit the disease-related burden. Long-term treatment modalities including the place for PTH replacement therapy and the optimal biochemical monitoring and imaging surveillance for complications to treatment in chronic HypoPT, need to be refined. The physiological changes in calcium metabolism occurring during pregnancy and lactation modify the clinical presentation and management of parathyroid disorders in these periods of life. Modern interdisciplinary approaches to PHPT and HypoPT in pregnant and lactating women and their newborns children are proposed. The recommendations on clinical management presented here will serve as background for further educational material aimed for a broader clinical audience, and were developed with focus on endocrinologists in training.