Surgery for primary hyperparathyroidism

Cost-effectiveness of one-stop-shop [18F]Fluorocholine PET/CT to localise parathyroid adenomas in patients suffering from primary hyperparathyroidism

PURPOSE

We conducted a cost-effectiveness analysis in which we compared a preoperative [18F]Fluorocholine PET/CT-based one-stop-shop imaging strategy with current best practice in which [18F]Fluorocholine PET/CT is only recommended after negative or inconclusive [99mTc]Tc-methoxy isobutyl isonitrile SPECT/CT for patients suffering from primary hyperparathyroidism. We investigated whether the one-stop-shop strategy performs as well as current best practice but at lower costs.

METHODS

We developed a cohort-level state transition model to evaluate both imaging strategies respecting an intraoperative parathyroid hormone monitored treatment setting as well as a traditional treatment setting. The model reflects patients' hospital journeys after biochemically diagnosed primary hyperparathyroidism. A cycle length of twelve months and a lifetime horizon were used. We conducted probabilistic analyses simulating 50,000 cohorts to assess joint parameter uncertainty. The incremental net monetary benefit and cost for each quality-adjusted life year were estimated. Furthermore, threshold analyses regarding the tariff of [18F]Fluorocholine PET/CT and the sensitivity of [99mTc]Tc-methoxy isobutyl isonitrile SPECT/CT were performed.

RESULTS

The simulated long-term health effects and costs were similar for both imaging strategies. Accordingly, there was no incremental net monetary benefit and the one-stop-shop strategy did not result in lower costs. These results applied to both treatment settings. The threshold analysis indicated that a tariff of €885 for [18F]Fluorocholine PET/CT was required to be cost-effective compared to current best practice.

CONCLUSION

Both preoperative imaging strategies can be used interchangeably. Daily clinical practice grounds such as available local resources and patient preferences should inform policy-making on whether a hospital should implement the one-stop-shop imaging strategy.

Clinical characteristics and outcomes of patients operated for primary hyperparathyroidism at Tampere University Hospital in 2017-2018

BACKGROUND AND OBJECTIVE

Studies on the outcomes of parathyroid surgery are scarce. The aim was to report the outcomes and to study the association between pre- and peri-operative information with the outcomes of patients operated for primary hyperparathyroidism.

METHODS

This was a retrospective, descriptive study with unselected patients treated surgically for primary hyperparathyroidism from a catchment population of 704,500 in Finland. Data were acquired from the electronic hospital registers based on parathyroid surgery procedure codes between 1 January 2017 and 31 December 2018. Preoperative data, surgical data, preoperative and postoperative laboratory values, histopathological findings, and postoperative clinical data were recorded.

RESULTS

During the 2-year study period, 149 patients with primary hyperparathyroidism were treated surgically with a 97% remission rate. Surgical complications included postoperative bleeding in two patients (1%) and vocal cord paralysis in one patient (0.6%). No postoperative infections were reported. Three patients (2%) developed postoperative hypoparathyroidism necessitating the use of alfacalcidol more than 1 month after surgery. Ionized calcium measured 0-1 days after surgery was not statistically significantly associated with remission or postoperative hypoparathyroidism. Serum parathyroid hormone (PTH) assessed 0-1 days postoperatively was associated with persistent disease, but not with postoperative hypoparathyroidism. The histopathological diagnosis was adenoma or hyperplasia in 112 patients (75%), atypical adenoma in 28 patients (19%), and carcinoma in five patients (3%). Patients with parathyroid carcinoma had higher preoperative ionized calcium and PTH values than those with adenoma or hyperplasia.

CONCLUSIONS

Most patients who were operated due to primary hyperparathyroidism achieved normocalcemia after surgery, and the frequency of complications was low. Ionized calcium taken 0-1 days after surgery was not associated with remission of hyperparathyroidism or postoperative hypoparathyroidism. High postoperative serum PTH predicted persistent disease.

Robotic resection of ectopic mediastinal parathyroid adenoma in multiple endocrine neoplasia 1

BACKGROUND

Hyperparathyroidism in patients with multiple endocrine neoplasia 1 is attributed to the excessive secretion of parathyroid hormone (PTH) from multiple parathyroid glands. This can be successfully treated through complete resection of the parathyroid glands; however, subsequent surgery is often required because of the presence of supernumerary or ectopic parathyroid glands. Therefore, identifying the locations of all functional glands is crucial for precise resection. Here, we report a case of ectopic mediastinal parathyroid adenoma that was successfully resected using robot-assisted thoracoscopic surgery.

CASE PRESENTATION

A 53-year-old woman underwent a total parathyroidectomy with autotransplantation for multiple endocrine neoplasia 1-associated primary hyperparathyroidism. The patient previously underwent laparoscopic distal pancreatectomy for a pancreatic neuroendocrine tumor. She also presented with a mediastinal tumor and nonfunctional pituitary adenoma that could be followed up. Blood tests before total parathyroidectomy showed high levels of intact PTH (183 pg/mL) and calcium (Ca; 10.3 mg/dL); however, postoperative blood tests still revealed high levels of intact PTH (103 pg/mL) and Ca (11.4 mg/dL). Computed tomography and magnetic resonance imaging revealed a 45-mm-sized mass in the right upper mediastinum as a well-defined solid and cystic lesion, whereas ^99mTc-methoxyisobutylisonitrile scintigraphy indicated a strong accumulation of tracers, suggesting an ectopic lesion in the mediastinum. Persistent hyperparathyroidism after total parathyroidectomy via neck incision was attributed to an ectopic parathyroid tumor in the mediastinum. Thus, we decided to resect the tumor using robot-assisted thoracoscopic surgery to perform the procedure gently and carefully. During surgery, a mediastinal tumor was identified as it was detected radiographically. Because it did not invade the surrounding tissues, it could be completely resected without injuring the capsule. The patient was discharged without complications. Postoperatively, Ca and intact PTH levels decreased back to normal. The final pathological diagnosis confirmed that the mass was an ectopic mediastinal parathyroid adenoma.

CONCLUSIONS

Minimally invasive surgical resection of a remnant ectopic lesion was successfully performed in a patient with multiple endocrine neoplasia 1 using robot-assisted thoracoscopic surgery.

Dual-Tracer Parathyroid Imaging Using Joint SPECT Reconstruction

Purpose

We assessed the lesion detection performance of the dual-tracer parathyroid SPECT imaging using the joint reconstruction method.

Materials and Methods

Thirty-six noise realizations were created from SPECT projections collected from an in-house neck phantom to emulate 99mTc-pertechnetate/99mTc-sestamibi parathyroid SPECT datasets. Difference images representing parathyroid lesions were reconstructed using the subtraction and the joint methods whose corresponding optimal iteration was defined as the iteration which maximized the channelized Hotelling observer signal-to-noise ratio (CHO-SNR). The joint method whose initial estimate was derived from the subtraction method at optimal iteration (the joint-AltInt method) was also assessed. In a study of 36 patients, a human-observer lesion-detection study was performed using difference images from the three methods at optimal iteration and the subtraction method with four iterations. The area under the receiver operating characteristic curve (AUC) was calculated for each method.

Results

In the phantom study, both the joint-AltInt method and the joint method improved SNR compared to the subtraction method at their optimal iteration by 444% and 81%, respectively. In the patient study, the joint-AltInt method yielded the highest AUC of 0.73 as compared with 0.72, 0.71, and 0.64 from the joint method, the subtraction method at optimal iteration, and the subtraction method at four iterations. At a specificity of at least 0.70, the joint-AltInt method yielded significantly higher sensitivity than the other methods (0.60 vs 0.46, 042, and 0.42; p < 0.05).

Conclusions

The joint reconstruction method yielded higher lesion detectability than the conventional method and holds promise for dual-tracer parathyroid SPECT imaging.

Evolution of the Diagnosis and Treatment of Primary Hyperparathyroidism

This study aims to present the evolution of our center's approach to treating primary hyperparathyroidism (PHPT) from diagnosis to intraoperative interventions. We have also evaluated the intraoperative localization benefits of indocyanine green fluorescence angiography. This retrospective single-center study involved 296 patients who underwent parathyroidectomy for PHPT between January 2010 and December 2022. The preoperative diagnostic procedure included neck ultrasonography in all patients, [99mTc]Tc-MIBI scintigraphy in 278 patients, and, in 20 doubtful cases, [18F] fluorocholine positron emission tomography (PET) computed tomography (CT) was performed. Intraoperative PTH was measured in all cases. Indocyanine green has been administered intravenously since 2020 to guide surgical navigation using a fluorescence imaging system. The development of high precision diagnostic tools that can localize an abnormal parathyroid gland in combination with intra-operative PTH assay (ioPTH) enables the surgical treatment of PHPT patients with focused approaches and excellent results that are stackable with bilateral neck exploration (98% of surgical success). Indocyanine green angiography has the potential to assist surgeons in identifying parathyroid glands rapidly and with minimal risk, especially when pre-operative localization has failed. When everything else fails, it is only an experienced surgeon who can resolve the situation.

Robotic resection of ectopic mediastinal parathyroid adenoma with intraoperative parathyroid hormone monitoring: a case report

Background

Primary hyperparathyroidism is a disease caused by the secretion of excess parathyroid hormone (PTH) owing to the enlargement of the parathyroid gland. Ectopic parathyroid glands exist in the mediastinum in approximately 1–2% of cases, which is relatively rare. Intraoperative monitoring of serum PTH level is important to assess whether the source of hyperparathyroidism has been eliminated.

Case presentation

A 53-year-old asymptomatic woman was diagnosed with ectopic mediastinal parathyroid adenoma. A three-port robotic partial resection of the thymus containing the tumor was attempted, but bleeding from a swollen pericardial diaphragmatic vein led to the addition of an assist port along the way. The PTH level was measured intraoperatively. After confirming that the 15-min PTH level after removal of the tumor was less than 50% of the baseline value, the operation was completed. The tumor was positive for PTH and was diagnosed as an ectopic mediastinal parathyroid adenoma. Some small ectopic parathyroid gland tissues were observed in other parts of the thymic tissue. Serum calcium and PTH levels decreased and normalized.

Conclusions

We report the usefulness of robotic resection for ectopic mediastinal parathyroid adenoma with PTH monitoring. However, histopathologically, small parathyroid gland tissues may remain in the surrounding thymus. Hence, we believe that a strict follow-up is required for parathyroid function in the future.

Comparisons Between Normocalcemic Primary Hyperparathyroidism and Typical Primary Hyperparathyroidism

BACKGROUND

Normocalcemic primary hyperparathyroidism (NPHPT) was first described in 2008. It is defined as consistently elevated serum parathyroid hormone (PTH) levels with normal serum calcium (sCa) concentration, after excluding secondary causes of PTH elevation. However, the exact definition and management strategy for NPHPT remain controversial. We retrospectively investigated the clinicopathological features and short-term outcomes of NPHPT patients.

METHODS

A total of 280 patients who were surgically indicated for primary hyperparathyroidism (PHPT) at the Yonsei Severance Medical Center between 2015 and 2019 were included. Patients were classified according to preoperative PTH, corrected sCa, and ionized calcium (iCa) levels as follows: typical primary hyperparathyroidism (TPHPT, elevated PTH, sCa, and iCa, n = 158) and NPHPT (elevated PTH, normal sCa, n = 122).

RESULTS

NPHPT was commonly seen in younger individuals (aged < 50 years, P = 0.025); nephrolithiasis and bone fractures were common. Preoperative PTH level was higher in the TPHPT group (P < 0.001). The NPHPT group had higher numbers of multiple parathyroid lesions (P = 0.004) that were smaller (P = 0.011). NPHPT patients were further divided into two subgroups according to iCa levels: the elevated (n = 95) and normal iCa (n = 27) groups. There was no significant difference between the two subgroups regarding symptoms and multiplicity of lesions.

CONCLUSION

We found that NPHPT may be a heterogeneous disease entity of PHPT with high rates of multi-gland disease, which appears to be biochemically milder but symptomatic. Intraoperative PTH monitoring might help increase the surgery success rate. Moreover, the short-term outcomes of NPHPT after surgery did not differ from that of TPHPT.

The Effect of the Frequently Used Cinacalcet for pHPT during the COVID-19 Pandemic on Perioperative Decrease in Parathyroid Hormone

Background: Cinacalcet is a calcimimetic drug that has increasingly been used as a bridging therapy for primary hyperparathyroidism (pHPT), especially during the COVID-19 pandemic. The aim of our study was to investigate if preoperative cinacalcet therapy affects intraoperative parathyroid hormone (IOPTH) monitoring during parathyroidectomy, which is an important indicator for the success of surgery. Methods: In this single-center retrospective analysis, we studied the outcomes of 72 patients who underwent surgery for pHPT. We evaluated two groups: those with cinacalcet therapy before operation—the cinacalcet group (CG)—and those without medical therapy preoperatively (non-CG). In order to perform a between-group comparison of time trends, we fit a linear mixed-effects model with PTH as the response variable and predictors PTH levels preoperatively, group (cinacalcet yes/no), time, the group-by-time interaction, and a random intercept (per subject). Results: Our cohort included 51 (71%) women and 21 (29%) men, who were operated upon for pHPT in the period from January 2018 until August 2021. All patients were diagnosed with pHPT and 54% of the cohort were symptomatic for hypercalcemia. Moreover, 30% of the patients were treated with cinacalcet as a bridging therapy preoperatively, and this increased during the COVID-19 pandemic, as 64% of this group were treated in the last two years. Calcium values were significantly different before (p < 0.001) and after (p = 0.0089) surgery, but calcium level change did not differ significantly between the CG and non-CG. Parathyroid hormone (PTH) levels dropped significantly in both groups during 10 min IOPTH monitoring (p < 0.001), but there was no significant difference between the two groups (p = 0.212). Conclusions: In the examined patient cohort, the use of cinacalcet did not affect the value of IOPTH monitoring during surgery for pHPT.

Parathyroid Imaging: Past, Present, and Future

The goal of parathyroid imaging is to identify all sources of excess parathyroid hormone secretion pre-operatively. A variety of imaging approaches have been evaluated and utilized over the years for this purpose. Ultrasound relies solely on structural features and is without radiation, however is limited to superficial evaluation. 4DCT and 4DMRI provide enhancement characteristics in addition to structural features and dynamic enhancement has been investigated as a way to better distinguish parathyroid from adjacent structures. It is important to recognize that 4DCT provides valuable information however results in much higher radiation dose to the thyroid gland than the other available examinations, and therefore the optimal number of phases is an area of controversy. Single-photon scintigraphy with 99mTc-Sestamibi, or dual tracer 99mTc-pertechnetate and 99mTc-sestamibi with or without SPECT or SPECT/CT is part of the standard of care in many centers with availability and expertise in nuclear medicine. This molecular imaging approach detects cellular physiology such as mitochondria content found in parathyroid adenomas. Combining structural imaging such as CT or MRI with molecular imaging in a hybrid approach allows the ability to obtain robust structural and functional information in one examination. Hybrid PET/CT is widely available and provides improved imaging and quantification over SPECT or SPECT/CT. Emerging PET imaging techniques, such as 18F-Fluorocholine, have the exciting potential to reinvent parathyroid imaging. PET/MRI may be particularly well suited to parathyroid imaging, where available, because of the ability to perform dynamic contrast-enhanced imaging and co-registered 18F-Fluorocholine PET imaging simultaneously with low radiation dose to the thyroid. A targeted agent specific for a parathyroid tissue biomarker remains to be identified.

Histopathological Features of Parathyroid Adenoma and 18F-Choline Uptake in PET/MR of Primary Hyperparathyroidism

BACKGROUND

The aim of this study was to assess the relationship between the histopathological properties of hyperfunctioning parathyroids and parathyroid 18F-choline uptake.

PATIENTS AND METHODS

A total of 31 parathyroid adenomas were retrospectively analyzed in patients with primary hyperparathyroidism and preoperative 18F-choline PET/MR. PET/MR parameters of parathyroid glands (SUVmax and target-to-background ratio in early-phase [EP] and late-phase [LP]), MRI volume, preoperative parathyroid hormone (PTH) serum concentration, and postoperative histopathology (predominant cell type and growth pattern of adenoma cells, location and size of adenoma) were assessed. The relationship of PET/MR parameters, PTH, and histological parameters was determined using linear regression, Spearman correlation and Kruskal-Wallis test.

RESULTS

The median volume of parathyroid adenoma was 421.78 ± 142.46 mm3 (46.39-4412.69). Adenomas were predominantly composed of chief, water-clear, and oncocytic/oxyphilic cells in 27/31, 2/31, and 2/31 cases, respectively. The growth pattern was predominantly solid, follicular, and trabecular in 18/31, 8/31, and 5/31, respectively. The SUVmax was 6.71 ± 3.39 in EP and 6.91 ± 3.97 in LP. Follicular growth pattern had slightly higher EP SUVmax (trabecular: 4.12 ± 0.56; solid: 6.62 ± 3.19; follicular: 8.56 ± 3.96; P = 0.046). Spearman correlation showed strong positive correlation between volume and both EP and LP SUVmax (0.626; P = 0.0001 and 0.576; P = 0.0001, respectively). Linear regression analysis revealed significant correlation between PTH level and EP and LP SUVmax (both P = 0.001); in contrast, no correlation was found between PTH level and both cell type and growth pattern.

CONCLUSIONS

Our findings suggest that 18F-choline uptake of parathyroid adenomas might be associated both with the histological growth pattern and adenoma volume, but not with a specific cell type.

Predictors of adenoma size and location in primary hyperparathyroidism

Purpose

In primary hyperparathyroidism (PHPT), intraoperative localization of the parathyroid adenoma can be challenging, especially in cases of negative preoperative imaging. Since a focused unilateral parathyroidectomy has benefits compared to a conventional bilateral neck exploration, the question arises whether adenoma size prediction can facilitate a targeted approach. We investigated whether single parathyroid adenoma size can be estimated using preoperative parathyroid hormone (PTH), calcium, and phosphate in patients with PHPT. Preoperative imaging accuracy was evaluated.

Methods

The data of 156 patients who underwent curative parathyroidectomy for single adenoma PHPT were analyzed retrospectively. Information obtained included laboratory data, imaging results, intraoperative data, and final pathology. Imaging accuracy was analyzed descriptively. The association between preoperative biochemical markers and adenoma dimensions was investigated using Spearman’s correlation coefficient and multivariable regression modeling.

Results

Cervical ultrasound correctly predicted adenoma laterality in 95.5%, sestamibi scintigraphy in 80.6%, both had lower true-positive rates for quadrant prediction. Patients with negative imaging results showed higher thyroid volumes than those with positive results. Adenoma volume was positively correlated with preoperative PTH (p < 0.001) and calcium (p < 0.001) and negatively correlated with preoperative phosphate (p = 0.001). Using these preoperative biochemical markers and patient age and BMI, adenoma volume can be significantly predicted using the multivariable regression algorithm.

Conclusion

Cervical ultrasound is superior to scintigraphy for predicting adenoma location and should be the first-choice imaging method, but both methods may be limited by increased thyroid volume. Large adenomas are more likely with higher PTH, higher calcium, and lower phosphate levels. In cases of undetermined adenoma location, an estimation of adenoma volume via our algorithm could corroborate sonographic volume measurements of the suspected adenoma.

Minimally invasive video-assisted parathyroidectomy (MIVAP) without intraoperative PTH determination

BACKGROUND

Minimally invasive video-assisted parathyroidectomy (MIVAP) has become a standard approach to primary hyperparathyroidism (pHPT) since described. Although intraoperative parathyroid hormone assay (IOPTH) has been generalized as a complementary technique to MIVAP, its actual impact on the surgical success of this technique is not without controversy. The aim of this study was to describe our results in the management of pHPT with successful preoperative localization, by MIVAP technique, without IOPTH determination, confirming in a larger series our preliminary results.

METHODS

A retrospective descriptive study was conducted in pHPT patients treated by MIVAP with no IOPTH determination in a tertiary hospital between 2007 and 2019.

RESULTS

A total of 167 patients were included in the study. Biochemical cure was achieved in 96.4%, and 94.1% did not present any surgical complication. The mean duration of surgery was 61 min, and the mean length of hospital stay was 1.8 days CONCLUSIONS: In case of positive preoperative localization studies, MIVAP is a safe and effective technique for the surgical treatment of pHPT due to a parathyroid adenoma, regardless of IOPTH determination, with a success rate > 95% and a low complication rate.

4D-CT facilitates focused parathyroidectomy in patients with primary hyperparathyroidism by maintaining a high negative-predictive value for uninvolved quadrants

INTRODUCTION

Improved preoperative localization facilitates minimally invasive parathyroidectomy for removal of parathyroid lesions therefore preventing an invasive bilateral neck exploration. As 4D-CT has emerged, its high specificity has helped with preoperative parathyroid lesion localization. A high negative predictive value (NPV) would serve to further confirm parathyroid lesion localization and limit unnecessary surgical exploration. This study's objective was to determine the NPV of preoperative 4D-CT and its facilitation of minimally invasive parathyroidectomy.

METHODS

A retrospective review was compiled for patients undergoing parathyroidectomy for primary hyperparathyroidism with a preoperative 4D-CT. Included patients were sorted into various groups for comparison: those with 4D-CT localizing to a single lesion, localizing to multiple lesions, and those with nonlocalizing findings; multiple hypercellular parathyroid gland versus single gland findings; extent of surgical exploration; lesion location; and patients with concomitant thyroid nodules. Negative predictive value was calculated and used to quantify the ability for 4D-CT to rule out biochemically significant parathyroid lesions.

RESULTS

In our review of 68 patients: sensitivity was 81.3%, specificity was 95.5%, positive predictive value was 87.1%, and negative predictive value was 93.3%. 86% had a single localizing 4D-CT, 7% had a non-localizing 4D-CT, and 7% had a multiple quadrant localizing 4D-CT. NPV for single and multi-localizing 4D-CT were 96.8% and 88.9%, respectively.

CONCLUSION

Preoperative 4D-CT has a high negative predictive value (93.3%), suggesting in the majority of cases, a quadrant with no 4D-CT radiographic findings suspicious for parathyroid is unlikely to harbor biochemically significant parathyroid lesions.

Spontaneous neck hematoma secondary to parathyroid adenoma: a case series

PURPOSE

Spontaneous neck hematoma is a rare yet potentially fatal complication of primary hyperparathyroidism (PHPT). Here we aim to describe novel presentations of neck hematomas secondary to PHPT, discussing tools and signs that facilitate diagnosis.

METHODS

Case series data were extracted by retrospective chart reviews of our institution's electronic medical records, including all neck hematoma cases from parathyroid origin between 2005 and 2020. Cases from PubMed and EMBASE between 1999 and 2020 were analyzed in a systematic literature review.

RESULTS

Four patients were identified with five acute bleeding events, including a novel report of recurrent neck hemorrhage due to parathyroid adenoma. There was postmenopausal female predominance (75%), consistent with previous reports (72.7%). Common presentations included neck pain, dysphagia and hoarseness. All bleedings spread into the retropharyngeal space. Vocal cord paralysis was found in a single case and in 8.6% of the benign lesions in the reviewed cases. A single case presented with normal calcium levels (20% of bleeding episodes), in line with the reviewed cases (17.4%). A subtle CT sign of an enhancing area within the parathyroid gland, which led to the diagnosis, was identified in a single case. Conservative treatments were employed in 80% of our cases and in 51.5% of the reviewed cases, all being successful. Neck explorations performed after a 3-month waiting period from the acute event demonstrated better results compared to immediate surgery.

CONCLUSION

A high suspicion index is needed, particularly in post-menopausal women, to reach a diagnosis and allow optimal management. Normal laboratory values do not exclude parathyroid etiology, yet assessment should include calcium and PTH levels along with targeted imaging. Since bleeding may recur, we suggest that PHPT complicated with neck hematoma should be an independent indication for definitive parathyroidectomy surgery.

LEVEL OF EVIDENCE

3b.

Retro-tracheal parathyroid adenoma: A rare location of a common pathology

Ectopic parathyroid adenoma in the mediastinum has been reported in several publications; however, its location in the posterior mediastinum, especially a retro-tracheal location, has been rarely reported. We report a case of a 61-year-old patient who presented with clinical symptoms of malignant hypercalcemia due to a retro-tracheal mediastinal parathyroid adenoma. The surgical excision normalized the phosphocalcic balance with improvement in the patient's clinical symptoms. An ectopic hypersecreting parathyroid adenoma with life-threatening hypercalcemia should prompt radiological assessment and appropriate surgical management to prevent significant clinical complications.

Main Surgical Principles and Methods in Surgical Treatment of Primary Hyperparathyroidism

The only curative treatment for primary hyperparathyroidism (pHPT) is surgery. The most important factors that increase the success rate of a parathyroidectomy are the establishment of the correct diagnosis and the surgeon's good knowledge of anatomy and embryology. The lower parathyroid glands develop from the dorsal portion of the third pharyngeal pouch, and the upper parathyroid glands from the fourth pharyngeal pouch. Humans typically have 4 parathyroid glands; however, more than 4 and fewer than 4 have been observed. Typically, the upper parathyroid glands are located in the cricothyroid junction area on the posterolateral portion of the middle and upper third of the thyroid, while the lower parathyroids are located in an area 1 cm in diameter located posterior, lateral, or anterolateral to the lower thyroid pole. Ectopic locations of parathyroid glands outside the normal anatomical regions due to the abnormal migration during embryological development or acquired ectopy due to migration of enlarged parathyroids are not uncommon. There are various surgical techniques to treat HPT; however, 2 main surgical options are used: bilateral neck exploration (BNE) and minimally invasive parathyroidectomy (MIP). While there are open, endoscopic, and video-assisted MIP (MIVAP) approaches, most often an open lateral MIP technique is used. In addition, endoscopic or robotic parathyroidectomy methods performed from remote regions outside the neck have been reported. Although currently MIP is the standard treatment option in selected patients with positive imaging, BNE remains the gold standard procedure in parathyroid surgery. In 80% to 90% of patients with pHPT, a pathological parathyroid gland can be detected with preoperative imaging methods and MIP can be applied. However, the pathological gland may not be found during a MIP procedure as a result of false positive results. The parathyroid surgeon must also know the BNE technique and be able to switch to BNE and change the surgical strategy if necessary. If the intended gland is not found in its normal anatomical site, possible embryological and acquired ectopic locations should be investigated. It should be kept in mind that MIP and BNE are not alternatives to each other, but rather complementary techniques for successful treatment in parathyroid surgery.

Ectopic parathyroid adenoma in the submandibular region: a case report

Ectopic parathyroid adenomas that affect the submandibular region have not been widely reported. We describe a 34-year-old man who presented with a painless swelling of the submandibular region. The identification of hypercalcaemia encouraged us to engage a multidisciplinary team to evaluate further serum changes. Parathyroid hormone analysis, ^99mTc-methoxy-isobutyl-isonitrile (^99mTc-MIBI) scintigraphy, and single-photon emission computed tomography (SPECT-CT) were done to rule out hyperparathyroidism. Raised parathyroid hormone together with ^99mTc-MIBI and SPECT-CT examination were consistent with a tumour caused by the hyperparathyroidism. Removal of the lesion resulted in rapid improvement in serum calcium and parathyroid hormone, and the normalisation of the serum creatinine, concentrations. Histopathological analysis confirmed a parathyroid adenoma. We conclude that ectopic parathyroid adenomas should be considered as part of a differential diagnosis for tumours of the submandibular region.

Surgical Treatment of Primary Hyperparathyroidism: Which Therapy to Whom?

Primary hyperparathyroidism (pHPT) is characterized by an increase in the levels of PTH and Ca, or one of these (Ca, PTH) as a result of a dysregulation of calcium (Ca) metabolism due to inappropriate excess parathyroid hormone (PTH) autonomously produced from one or more than one parathyroid glands. Ninety to 95% of pHPT is a sporadic type, which is not associated with the familial history and other endocrine organ tumors, and 5-10% of it is hereditary. While 80-85% of pHPT arises from a single parathyroid adenoma, 4-5% is caused by a double adenoma, 10-15% by multigland hyperplasia and less than 1% by parathyroid cancer. The diagnosis of pHPT is reached biochemically. The only curative treatment of pHPT is surgery. The choice of surgery in pHPT may vary depending on whether the patient has hereditary HPT or thyroid disease requiring surgical treatment, preoperative localization studies and the findings in these studies, the possibilities of using intraoperative PTH and the preference of the surgeon. The preoperatively determined surgical strategy can be revised according to intraoperative findings in case of need to achieve excellent results. The two main approaches in the surgical treatment of pHPT are BNE (bilateral neck exploration) and MIP (minimal invasive parathyroidectomy). Although BNE is a consistently valid option that has excellent results in the surgical treatment of pHPT and is considered the gold standard, MIP is the ideal approach in selected patients with clinically and radiologically considered a single-gland disease. Negative imaging is not a contraindication for parathyroid surgery and is not a criterion for the presence or absence of surgical indication. Although both methods are safe and effective in the surgical treatment of sporadic pHPT, there is still controversy regarding the effectiveness of both methods. Surgical intervention should establish the risk-benefit balance well, minimize the risk of persistent and recurrent disease and provide the highest cure rate without increasing the risk of complications. Complication rates are higher in the secondary surgery, thus in secondary procedures, selective surgery should be performed under guidance of an imaging modality. The surgical strategy should be determined to achieve maximum cure with minimum dissection and minimal morbidity. In this study, we aimed to determine the type of surgical treatment and pHPT patients suitable for the surgical treatment.

American Head and Neck Society Endocrine Surgery Section update on parathyroid imaging for surgical candidates with primary hyperparathyroidism

Health care consumer organizations and insurance companies increasingly are scrutinizing value when considering reimbursement policies for medical interventions. Recently, members of several American Academy of Otolaryngology-Head & Neck Surgery (AAO-HNS) committees worked closely with one insurance company to refine reimbursement policies for preoperative localization imaging in patients undergoing surgery for primary hyperparathyroidism. This endeavor led to an AAO-HNS parathyroid imaging consensus statement (https://www.entnet.org/content/parathyroid-imaging). The American Head and Neck Society Endocrine Surgery Section gathered an expert panel of authors to delineate imaging options for preoperative evaluation of surgical candidates with primary hyperparathyroidism. We review herein the current literature for preoperative parathyroid localization imaging, with discussion of efficacy, cost, and overall value. We recommend that planar sestamibi imaging, single photon emission computed tomography (SPECT), SPECT/CT, CT neck/mediastinum with contrast, MRI, and four dimensional CT (4D-CT) may be used in conjunction with high-resolution neck ultrasound to preoperatively localize pathologic parathyroid glands. PubMed literature on parathyroid imaging was reviewed through February 1, 2019.

Management of familial hyperparathyroidism syndromes: MEN1, MEN2, MEN4, HPT-Jaw tumour, Familial isolated hyperparathyroidism, FHH, and neonatal severe hyperparathyroidism

While primary hyperparathyroidism (PHPT) generally represents a common endocrine disorder, being the more frequent cause of hypercalcemia in outpatients, familial forms of PHPT (FPHPT) account for no more than 2-5% of the overall PHPT. In the last decades, many technical progresses in both molecular and biochemical-radiological evaluation have been made, and substantial advancements in understanding these disorders have been reached. Differences both in the pathogenesis and clinical presentation exist among the various hyperparathyroid syndromic forms, and, since FPHPT is frequently associated to other endocrine, proliferative and/or functional disorders, as also non-endocrine tumours, with varying clinical spectrum of occurrence in each syndrome, its early clinically detection for appropriately preventing complications (i.e. kidney and bone disorders) is strictly advised. In this review, the clinical-biochemical features and diagnostic procedures of each FPHPT form will be summarized and a general overview on surgical and pharmacological approaches to FPHPT has been also considered.

An Unusual Mass of Posterior Mediastinum: A Case of Retrotracheal Parathyroid Adenoma Presenting With Primary Hyperparathyroidism

Although parathyroid ectopy in the mediastinum has been the subject of several publications, its location in the posterior mediastinum is very rarely reported. We report a case of a 69-year-old patient who presented with clinical symptoms of malignant hypercalcemia due to a retrotracheal mediastinal parathyroid adenoma. The surgical excision leads to a quick normalisation of the phosphocalcic balance with improvement of the clinical symptoms. Ectopic hypersecreting parathyroid adenoma with life-threatening hypercalcemia should prompt radiological assessment and appropriate surgical management to prevent further clinical complications.

The diagnostic value of parathyroid hormone washout in primary hyperparathyroidism patients with negative or equivocal 99 m Tc-MIBI results

BACKGROUND AND OBJECTIVES

The accurate identification of hyper functioning parathyroid gland is needed for definitive surgical treatment in primary hyperparathyroidism. Ultrasonography and 99mTechnetium sestamibi scintigraphy are the two most used methods with varying sensitivities. This study aimed to assess the value of parathyroid hormone (PTH) assay in preoperative ultrasound guided fine needle aspiration (FNA)-PTH washout fluid to verify the correct localisation of lesions with negative or inconclusive scintigraphy results.

METHODS

We evaluated data of 28 lesions in 21 patients who underwent US-guided parathyroid fine-needle aspiration (FNA) with PTH washout, retrospectively. The PTH washout results and the reports of parathyroid surgery and imaging studies were reviewed.

RESULTS

Of operated 28 lesions 23 had positive and 5 had negative washout results. The median FNA-PTH washout was 2315.5 pg/ ml (min-max: 12.3-6978 pg/ ml). The calculated sensitivity of FNA-PTH washout was 85.7% and the specifity was 28.6%. The positive and negative predictive values were 78.3% and 40.0%, respectively.

CONCLUSIONS

FNA-PTH can be used to establish the nature of the lesion, discriminate parathyroid gland from thyroid lesions or cervical lymph nodes, improving the surgical outcomes. It can be used to localise parathyroid lesions preoperatively when negative or discordant ultrasound and scintigraphy findings are obtained.

MIBI scintigraphy of parathyroid adenomas: correlation with biochemical and histological markers

PURPOSE

In this study, we tested the hypothesis that MIBI-positive and MIBI-negative adenomas of parathyroid glands (APGs) have distinct biochemical and histological markers that could help differentiate MIBI-positive from MIBI-negative APGs.

PATIENTS AND METHODS

40 patients with 41 APGs were included in the study. Patients were enrolled in the study after MIBI scintigraphy examinations had been carried out. Biochemical analyses included serum levels of calcium (Ca), intact parathyroid hormone (iPTH), and 25-hydroxyvitamin D3 (25-OH-D3). All patients had neck ultrasound and MIBI examinations. After surgical resection the APGs were examined histologically.

RESULTS

In each of 39 patients one APG could be confirmed by histology, and in one patient, two contralateral APGs were identified. MIBI studies were positive in 73 % and negative in 27 % of the APGs. False-positive cases were not observed. MIBI-negative APGs were only present in patients with iPTH values below 150 pg/ml. In 82 % of MIBI negative studies oxyphilic cells were absent, and this cell type was present in only 18 % of MIBI negative cases (p < 0.001). Regarding cysts within the APGs, no differences were demonstrated between MIBI positive or negative studies (p = 0.32). Fat cells were seen in none of the MIBI -negative studies and in only 3 % of MIBI positive studies (p = 0.08).

CONCLUSIONS

For APGs, MIBI positivity correlates with serum iPTH concentration. The absence of oxyphilic cells with large numbers of mitochondria in APGs contributes to MIBI negativity, probably because of the reduced binding sites for the radiotracer.

Management and outcomes of hyperparathyroidism: a case series from a single institution over two decades

Background

Hyperparathyroidism is a frequent endocrine disorder with variable clinical manifestations and outcomes. We aimed to evaluate clinical presentations, management and outcomes of hyperparathyroidism.

Methods

A retrospective study was conducted to include all patients presented with hyperparathyroidism between 1995 and 2014 at a single tertiary hospital with an average follow-up period of 46 months. Data were reviewed for clinical presentations, diagnostic work-up, intraoperative findings, management, and outcomes.

Result

We identified 161 patients with hyperparathyroidism; 69% were females and the mean age was 49.4±15 years. Patients presented mainly with musculoskeletal (65.8%), renal (37.3%), gastrointestinal tract (53.8%) and neuropsychiatric (8.8%) manifestations. At presentation, mean serum calcium and parathyroid hormone levels were elevated while mean vitamin D level was lower. Sestamibi-^99mTc (MIBI) scintigraphy was done for 134 patients (83.2%) and was positive in 94 (70%). Primary hyperparathyroidism (67.7%) was the most frequent diagnosis followed by secondary (29.8%) and tertiary hyperparathyroidism (2.5%). The frequent indication for surgery was hypercalcemia (67.3%), bone disease (35.6%) and renal calculi (28.9%). The main postoperative pathology was parathyroid adenoma (63.1%) followed by hyperplasia (37.3%). Fourteen (8.9%) and 18 (11.4%) patients had persistent and recurrent hyperparathyroidism, respectively. Autotransplantation of parathyroid tissue was done in 36 cases.

Conclusion

Primary hyperparathyroidism is the most frequent cause of the parathyroid disease. Parathyroidectomy is the effective surgical approach in symptomatic patients. Further studies are needed to establish the association between vitamin D levels, renal disorders and persistent or recurrent hyperparathyroidism.

Transoral robotic resection of a retropharyngeal parathyroid adenoma: a case report

Transoral robotic surgery (TORS) has become an increasingly popular option for early malignancies of the oropharynx. It offers superior visualization and has been proven to have acceptable functional and oncologic outcomes. Additionally, indications in head neck have expanded to manage tumors of the thyroid, neck, parapharyngeal space and salivary glands. A 58-year-old female had an incidental finding on CT imaging of a retropharyngeal mass at the level of the hyoid bone. She was referred to a tertiary medical center for further workup and removal of this mass. Due to the midline position of the mass, favorable access and potentially decreased surgical morbidity, TORS excision of the mass was performed for diagnosis and treatment. Histopathology confirmed this to be a hypercellular parathyroid mass consistent with parathyroid adenoma. We report a relatively unusual location of parathyroid adenoma in an asymptomatic patient with normal parathyroid and calcium levels. TORS proves to be a feasible and safe method for complete surgical excision of retropharyngeal parathyroid adenoma without tumor spillage or violation.

Factors Influencing Time to Decrease in Intraoperative Parathyroid Hormone (ioPTH) Levels in Patients Undergoing Focused Parathyroidectomy (FP)

The aim of this study was to evaluate potential factors affecting the time period in which a 50 per cent parathyroid hormone (PTH) drop is observed. Eight-seven patients undergoing focused parathyroidectomy between 2011 and 2015, whose PTH values dropped to within normal range, were grouped according to whether they required > or ≤15 minutes after gland excision to achieve a 50 per cent PTH. Groups were compared according to preoperative PTH, calcium, age, glomer-ular filtration rate, and adenoma weight. Lower preoperative and preincision PTH levels were associated with requiring >15 minutes to achieve a >50 per cent drop in ioPTH. Time to >50 per cent ioPTH drop did not affect cure rates at one year, though a >15 minutes requirement was associated with higher serum calcium levels (P = 0.015). Lower baseline PTH and preincision PTH levels are significantly associated with a >15 minutes postexcision time to achieve a >50 per cent drop in ioPTH. Future analyses are warranted to determine whether a longer postexcision time threshold before proceeding with four-gland exploration is warranted in patients with primary hyperparathyroidism and mildly elevated preoperative PTH.

Proteomics Analysis of Tissue Samples Reveals Changes in Mitochondrial Protein Levels in Parathyroid Hyperplasia over Adenoma

BACKGROUND/AIM

To unveil the pathophysiology of primary hyperparathyroidism, molecular details of parathyroid hyperplasia and adenoma have to be revealed. Such details will provide the tools necessary for differentiation of these two look-alike diseases. Therefore, in the present study, a comparative proteomic study using postoperative tissue samples from the parathyroid adenoma and parathyroid hyperplasia patients was performed.

MATERIALS AND METHODS

Protein extracts were prepared from tissue samples (n=8 per group). Protein pools were created for each group and subjected to DIGE and conventional 2DE. Following image analysis, spots representing the differentially regulated proteins were excised from the and used for identification via MALDI-TOF/TOF analysis.

RESULTS

The identities of 40 differentially-expressed proteins were revealed. Fourteen of these proteins were over-expressed in the hyperplasia while 26 of them were over-expressed in the adenoma.

CONCLUSION

Most proteins found to be over-expressed in the hyperplasia samples were mitochondrial, underlying the importance of the mitochondrial activity as a potential biomarker for differentiation of parathyroid hyperplasia from adenoma.

Preoperative parathyroid localization using joint planar imaging

The conventional approach for preoperative parathyroid localization with the dual ^99mTc-sestamibi (^99mTc-MIBI) and ^99mTc-pertechnetate (^99mTcO₄^- ) scintigraphy technique obtains the differential image by subtracting images from the two scans; the former depicts both the thyroid and parathyroid glands while the latter depicts the thyroid only. In this study, we developed a novel method based on Poisson noise modeling and maximum-likelihood estimation to generate the differential image in an iterative fashion using both planar images jointly. We demonstrated improved performance of our joint method as compared with the subtraction method in both phantom and patient studies. In the phantom study, we acquired two noise-free planar datasets using ^99mTc on an in-house thyroid phantom and a "lesion" bead (representing a parathyroid gland) with the same attenuation background as the thyroid phantom. These two planar datasets were combined and scaled to simulate noise-free clinical MIBI (four lesion-to-background contrast (LBC) values: 1.2, 1.3, 1.4 and 1.5), and ^99mTcO₄^- datasets. One-hundred Poisson noise realizations were generated for each datasets. The mean and standard deviation (SD) of the lesion contrast in the differential images were computed for both the subtraction and the joint methods. We also applied both the subtraction and the joint methods to one parathyroid patient dataset. The voxel-wise mean-to-SD ratios in four hyperfunctioning parathyroid lesions were calculated. The phantom results showed that the joint method at the 50^th iteration yielded a significant SD reduction compared with the subtraction method ranging from 20% to 45% (p <; 0.05). Similarly, the voxel-wise mean-to-SD ratios were substantially improved in the patient study from 0.40-1.60 (subtraction) to 2.68-3.16 (joint).

Unusual presentations of enlarged parathyroid cysts: two case reports

INTRODUCTION

Parathyroid cysts are infrequently encountered and have a variable presentation pattern depending on their size, location and secreting character.

PATIENTS AND METHODS

We report two cases of parathyroid cysts characterized by their uncommon clinical presentation.

RESULTS

In the first case the patient presented with a large cervical cystic mass without hypercalcemia, while in the second case, the patient experienced a hypercalcemic crisis associated with acute renal failure. The variable pattern of clinical manifestations is discussed.

CONCLUSION

Parathyroid cysts are a rare entity. Surgical resection is the key to therapy when hyperparathyroidism or local compression are identified.

Association of Parathyroid Gland Biopsy Excision Technique With Ex Vivo Radiation Counts During Radioguided Parathyroid Surgery

Importance

Parathyroid biopsy represents a means for normal and hyperfunctional glands to be distinguished intraoperatively. However, no data exist to guide surgeons regarding how much of a parathyroid gland must be biopsied to satisfy the 20% rule.

Objective

To quantify the relative proportion of a hyperfunctional parathyroid gland that must be evaluated with the gamma probe to satisfy the 20% rule.

Design, Setting, and Participants

A retrospective review of surgical data for 24 consecutive patients (16 women, 18 men; mean [SD] age, 66.6 [10] years; range, 51-83 years) who underwent surgery for primary hyperparathyroidism between May and October, 2015, in a tertieary academic medical center.

Main Outcomes and Measures

Extirpated parathyroid glands were sectioned into parallel or pie-shaped biopsies and evaluated ex vivo with a gamma probe to determine what percentage of a hyperfunctional gland must be sampled to meet the Norman 20% rule. The hypothesis was formulated during data collection.

Results

In total, 253 ex vivo biopsy specimens were obtained from 33 surgically removed parathyroid glands. Parathyroid biopsies satisfied the 20% rule with an accuracy that depended on the relative proportion of the parent gland represented: half or more (96.6%; 95% CI, 91.7%-100.0%), a quarter to one-half (87.0%; 95% CI, 79.3%-94.7%), less than a quarter (63.6%; 95% CI, 54.5%-72.8%). When less than a quarter of the gland was removed, pie-shaped biopsies were more likely to satisfy the 20% rule compared with parallel biopsies of the same weight (78.4% vs 56.2%; absolute difference, 22.2%; 95% CI, 4.7%-39.7%).

Conclusions and Relevance

Unless half of a parathyroid gland is biopsied during radioguided parathyroidectomy, the 20% rule cannot reliably rule out the presence of a hyperfunctional parathyroid lesion. Pie-shaped biopsies originating from the center of the gland are associated with a lower rate of false-negative results compared with peripheral biopsies of similar size. Pie-shaped biopsies and biopsy of half or more of each nonexcised parathyroid gland for ex vivo counts may increase the risk of remnant devascularization and resultant hypoparathyroidism.

A rare case of mediastinal functioning parathyroid adenoma removed successfully with thoracoscopy

We report here a rare case of primary hyperparathyroidism that was associated with an ectopic parathyroid adenoma located in the mediastinum. A 66-year-old woman suffering from primary hyperparathyroidism had been followed-up on an outpatient basis for over 10 years. She suffered from persistent urolithiasis and osteopenia due to hypercalcemia. After technetium-99-sestamibi (99mTc-MIBI) scintigraphy revealed an ectopic adenoma in the superior mediastinum, thoracoscopic resection of the tumor was performed. Subsequently, her serum parathyroid hormone (PTH) level decreased dramatically and her serum calcium concentration was restored to normal. Two years following surgery, her serum PTH and Ca levels remain stable.

Preoperative Localization Studies in Primary Hyperparathyroidism

Primary hyperparathyroidism (pHPT) is the third most frequently seen endocrine disease and it is the most common cause of hypercalcemia seen in ambulatory patients. PHPT is most often (80%-85%) caused by a single parathyroid adenoma, followed by double adenoma (4%-5%), multiple gland hyperplasia (10%-15%), and parathyroid carcinoma (<1%). The diagnosis of pHPT is biochemically established and the only curative treatment is surgery. Since the cause of pHPT is typically single-gland disease, it is possible to determine the majority of pathological glands with preoperative localization methods and use the minimally invasive parathyroidectomy (MIP) approach. MIP has become the standard treatment for pHPT in selected patients. There are both noninvasive and invasive preoperative localization methods. Noninvasive methods currently used include ultrasonography (US), parathyroid scintigraphy, 4-dimensional computed tomography (CT), magnetic resonance imaging, and positron emission tomography-CT with 18F-fluoroquinolone and 11C-methionine. Preoperative invasive localization methods include parathyroid hormone (PTH) measurement with fine-needle aspiration biopsy, lateralization with PTH measurement via bilateral jugular vein sampling, selective venous sampling, and parathyroid arteriography. The aim of this study was to evaluate preoperative localization studies used in cases of pHPT.

Localization of Parathyroid Adenoma With Real-Time Ultrasound: Freehand SPECT Fusion

Preoperative localization of parathyroid adenoma in primary hyperparathyroidism gains in importance as there is a trend toward minimally invasive parathyroid surgery. Besides MRI, 4-dimensional CT, PET/CT, invasive-selective venous sampling, or angiography, both ultrasound and scintigraphy are standard of care for lesion localization. Here we report on a 53-year-old woman with suspicion of primary hyperparathyroidism using real-time fusion of scintigraphic (freehand SPECT) and ultrasound imaging for adenoma localization. Real-time fusion of ultrasound and freehand SPECT allowed noninvasive dedicated metabolic and anatomic adenoma localization and treatment planning.

Elevated PTH with normal serum calcium level: a structured approach

Normocalcaemic hyperparathyroidism is a common biochemical finding, usually identified during an assessment of bone or renal health. Hypercalcaemia must be considered by calculation of adjusted calcium, and a careful history taken to assess dietary calcium intake and for the possibility of a malabsorption syndrome. 25-hydroxyvitamin D (25OHD) should be measured and replaced if indicated. The management plan for the patient is influenced by the context in which calcium and PTH were measured. In this brief review we describe the assessment of a patient with normocalcaemic hyperparathyroidism.

Point-of-care diagnostics for niche applications

Point-of-care or point-of-use diagnostics are analytical devices that provide clinically relevant information without the need for a core clinical laboratory. In this review we define point-of-care diagnostics as portable versions of assays performed in a traditional clinical chemistry laboratory. This review discusses five areas relevant to human and animal health where increased attention could produce significant impact: veterinary medicine, space travel, sports medicine, emergency medicine, and operating room efficiency. For each of these areas, clinical need, available commercial products, and ongoing research into new devices are highlighted.

Delayed Calcium Normalization After Presumed Curative Parathyroidectomy is Not Associated with the Development of Persistent or Recurrent Primary Hyperparathyroidism

BACKGROUND

Following parathyroidectomy for primary hyperparathyroidism (pHPT), serum calcium levels typically normalize relatively quickly. The purpose of this study was to identify potential factors associated with delayed normalization of calcium levels despite meeting intraoperative parathyroid hormone (IOPTH) criteria and to determine whether this phenomenon is associated with higher rates of persistent pHPT.

METHODS

This was a retrospective review of 554 patients who underwent parathyroidectomy for sporadic pHPT from January 2009 to July 2013. Patients who underwent presumed curative parathyroidectomy and had elevated POD0 calcium levels (>10.2 mg/dL) were matched 1:2 for age and gender to control patients with normal POD0 calcium levels.

RESULTS

Of the 554 patients, 52 (9 %) had an elevated POD0 Ca (median 10.7, range 10.3-12.2). Compared with the control group, these patients had higher preoperative calcium (12 vs. 11.1, p < 0.001) and PTH (144 vs. 110 pg/mL, p = 0.004) levels and lower 25OH vitamin D levels (26 vs. 31 pg/mL; p = 0.024). Calcium normalization occurred in 64, 90, and 96 % of patients by postoperative days (POD) 1, 14, and 30, respectively. There was no difference in rates of single-gland disease or cure rates between the groups.

CONCLUSIONS

After presumed curative parathyroidectomy, nearly 10 % of patients had transiently persistent hypercalcemia. Most of these patients had normal serum calcium levels within the first 2 weeks and did not have increased rates of persistent pHPT. Immediate postoperative calcium levels do not predict the presence of persistent pHPT, and these patients may not require more stringent follow-up.

Persistent Primary Hyperparathyroidism, Severe Vitamin D Deficiency, and Multiple Pathological Fractures

Persistent primary hyperparathyroidism (PHPT) refers to the sustained hypercalcemia state detected within the first six months following parathyroidectomy. When it coexists with severe vitamin D deficiency, the effects on bone can be devastating. We report the case of a 56-year-old woman who was sent to this center because of persistent hyperparathyroidism. Her disease had over 3 years of evolution with nephrolithiasis and hip fracture. Parathyroidectomy was performed in her local unit; however, she continued with hypercalcemia, bone pain, and pathological fractures. On admission, the patient was bedridden with multiple deformations by fractures in thoracic and pelvic members. Blood pressure was 100/80, heart rate was 86 per minute, and body mass index was 19 kg/m². Calcium was 14 mg/dL, parathormone 1648 pg/mL, phosphorus 2.3 mg/dL, creatinine 2.4 mg/dL, urea 59 mg/dL, alkaline phosphatase 1580 U/L, and vitamin D 4 ng/mL. She received parenteral treatment of hypercalcemia and replenishment of vitamin D. The second surgical exploration was radioguided by gamma probe. A retroesophageal adenoma of 4 cm was resected. Conclusion. Persistent hyperparathyroidism with severe vitamin D deficiency can cause catastrophic skeletal bone softening and fractures.

Clinicopathological correlates of hyperparathyroidism

Hyperparathyroidism is a common endocrine disorder with potential complications on the skeletal, renal, neurocognitive and cardiovascular systems. While most cases (95%) occur sporadically, about 5% are associated with a hereditary syndrome: multiple endocrine neoplasia syndromes (MEN-1, MEN-2A, MEN-4), hyperparathyroidism-jaw tumour syndrome (HPT-JT), familial hypocalciuric hypercalcaemia (FHH-1, FHH-2, FHH-3), familial hypercalciuric hypercalcaemia, neonatal severe hyperparathyroidism and isolated familial hyperparathyroidism. Recently, molecular mechanisms underlying possible tumour suppressor genes (MEN1, CDC73/HRPT2, CDKIs, APC, SFRPs, GSK3β, RASSF1A, HIC1, RIZ1, WT1, CaSR, GNA11, AP2S1) and proto-oncogenes (CCND1/PRAD1, RET, ZFX, CTNNB1, EZH2) have been uncovered in the pathogenesis of hyperparathyroidism. While bi-allelic inactivation of CDC73/HRPT2 seems unique to parathyroid malignancy, aberrant activation of cyclin D1 and Wnt/β-catenin signalling has been reported in benign and malignant parathyroid tumours. Clinicopathological correlates of primary hyperparathyroidism include parathyroid adenoma (80-85%), hyperplasia (10-15%) and carcinoma (<1-5%). Secondary hyperparathyroidism generally presents with diffuse parathyroid hyperplasia, whereas tertiary hyperparathyroidism reflects the emergence of autonomous parathyroid hormone (PTH)-producing neoplasm(s) from secondary parathyroid hyperplasia. Surgical resection of abnormal parathyroid tissue remains the only curative treatment in primary hyperparathyroidism, and parathyroidectomy specimens are frequently encountered in this setting. Clinical and biochemical features, including intraoperative PTH levels, number, weight and size of the affected parathyroid gland(s), are crucial parameters to consider when rendering an accurate diagnosis of parathyroid proliferations. This review provides an update on the expanding knowledge of hyperparathyroidism and highlights the clinicopathological correlations of this prevalent disease.

No Need to Abandon Focused Unilateral Exploration for Primary Hyperparathyroidism with Intraoperative Monitoring of Intact Parathyroid Hormone

BACKGROUND

We investigated the rate of persistent and recurrent hyperparathyroidism after focused unilateral exploration (UE) with intraoperative monitoring of intact parathyroid hormone (IOPTH).

STUDY DESIGN

A prospective cohort of 915 patients with primary hyperparathyroidism (PHP) underwent parathyroid surgery by a single surgeon from January 2003 to September 2013. A total of 556 patients with at least a single positive preoperative localization by ultrasound (US) and/or sestamibi scan (STS) underwent UE with IOPTH. The criterion for completion of surgery was an IOPTH fall of 50% from the highest intraoperative level and into the normal range 5 to 10 minutes after resection of the localized gland.

RESULTS

Fifteen patients had either persistent or recurrent PHP, yielding a 2.7% (95% CI 1.6% to 4.4%) overall recurrence rate based on the refined Wilson method with continuity correction. Four patients had persistent PHP. Three of these patients were cured with reoperation, and the fourth patient was followed nonoperatively. Eleven patients had recurrent PHP, with 5 corrected by surgery and 6 patients followed nonoperatively. The mean postoperative serum calcium (Ca) level was 9.4 mg/dL over a mean follow-up interval of 44.0 months. Preoperative localization rates by each localization study were: US 74.3% (n = 413), STS 86.9% (n = 483), and US and STS 71.4% (n = 397). There was no difference in the preoperative study that localized the hyperfunctional parathyroid gland in recurrent vs nonrecurrent patients by the Fisher's exact test (US, p =1.00; STS, p =0.65; US and STS, p =1.00).

CONCLUSIONS

The low rate of recurrent PHP after focused unilateral exploration with IOPTH suggests that this procedure should not be abandoned.