Current predictive models do not accurately differentiate between single and multi gland disease in primary hyperparathyroidism: a retrospective cohort study of two endocrine surgery units

Parathyroid near-infrared autofluorescence use for parathyroidectomy in mild primary hyperparathyroidism: Results from a randomized monocentric trial

BACKGROUND

Multiglandular parathyroid disease, which is particularly frequent in patients with mild primary hyperparathyroidism, is a surgical challenge requiring bilateral cervicotomy with 4-gland exploration. Near-infrared autofluorescence of the parathyroid is increasingly used to prevent hypocalcemia after total thyroidectomy. However, its utility in decreasing operating time and aiding parathyroid identification during bilateral 4-gland exploration remains debated.

METHODS

In our prospective trial, we enrolled consecutive patients with sporadic mild primary hyperparathyroidism (serum calcium <2.85 mmol/L with elevated or nonadapted serum parathyroid hormone levels). With randomization, we assigned patients to classic parathyroidectomy or parathyroidectomy with near-infrared autofluorescence using the Fluobeam 800 device (near-infrared autofluorescence group). All procedures involved planned bilateral neck exploration conducted by 2 experienced surgeons. The primary outcome was mean operating time. Secondary outcomes included the number of visualized and excised glands, complication rates, and cure rates.

RESULTS

In total, 132 patients were included (66 per group). Mean age was 64.0 ± 12.0 years, with 85.6% female. Mean preoperative serum calcium level was 2.63 ± 0.11 mmol/L, and median serum PTH level 86.1 [65.6-109.8] pg/mL. The mean operating time did not significantly differ between the classic parathyroidectomy and near-infrared autofluorescence groups (46.9 ± 15.3 minutes and 51.2 ± 22.9 minutes, respectively, P = .21). The use of near-infrared autofluorescence did not significantly modify the number of identified or resected glands nor the rate of complications. Cure rates were similar between groups (92.2% and 94.8%; P = .72).

CONCLUSION

In this study, near-infrared autofluorescence, in the hands of experienced surgeons, did not reduce operating time for parathyroidectomy during bilateral neck exploration in mild primary hyperparathyroidism. Although not increasing operating time, further evaluation is needed, particularly regarding its role in the surgeon's training.

Clinical predictors of negative/equivocal SPECT imaging outcomes in primary hyperparathyroidism: Factors calling for 18F-choline-PET

PURPOSE

For minimally invasive surgery of parathyroid adenomas, exact localization diagnostics are essential. Main imaging modalities used for diagnostics are sonography, SPECT with/without CT (traditional imaging) and 18F-choline-PET. The aim of our study was to identify predictors for inconclusive SPECT imaging and subsequently determine in which cases 18F-choline-PET is needed.

METHODS

Retrospective analysis of 138 patients with histologically confirmed primary hyperparathyroidism (pHPT). After sonography, patients underwent SPECT or SPECT/CT imaging, with subsequent 18F-choline-PET in cases of disconcordant results. Logistic regression analysis was used to identify clinical and laboratory factors predictive for negative SPECT results.

RESULTS

Sensitivity rates for sonography, SPECT, SPECT/CT, and choline-PET were 47 %, 49 %, 71.7 %, and 97 %, respectively. Logistic regression revealed lower PTH levels (p < 0.001), presence of structural thyroid disease (p = 0.018), and negative sonography (p < 0.001) as predictive of negative/equivocal SPECT outcome. An additional traditional imaging CT scan to a SPECT enhanced detection odds, as did greater adenoma weight. Urolithiasis, osteoporosis, and calcium values as measurement of activity and duration of disease showed no significant association with the detection rate. Furthermore, our study demonstrated that 18F-choline-PET exhibited remarkable sensitivity in detecting adenomas among patients with negative/equivocal SPECT results.

CONCLUSION

Our study reveals potential predictive factors for a negative/equivocal SPECT outcome in pHPT. Identifying these factors might allow minimizing futile SPECT examinations and perhaps encourage timely utilization of 18F-choline-PET imaging. Our study reinforces the clinical significance of 18F-choline-PET, especially in complex cases with disconcordant results by conventional parathyroid imaging methods.

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.

Usefulness of Ultrasonographic Detective Flow Imaging for Detecting Parathyroid Tumors: A Report of Two Cases

Parathyroid tumors (PTs) are sometimes difficult to diagnose because they are small and have low-velocity blood flow, which can be missed by current imaging modalities. PTs consist of parathyroid adenoma (PA), parathyroid cyst, and parathyroid carcinoma (PC). Detective flow imaging (DFI) is a new imaging technology that displays low-velocity blood flow. Herein, we report two cases in which DFI was useful for diagnosis of PTs. One patient had a PA and a parathyroid cyst in close proximity, and the other had a PC. To our knowledge, this is the first report to demonstrate the usefulness of DFI in the diagnosis of PTs.

An Ectopic Parathyroid Adenoma of the Retropharynx in a Patient with Primary Hyperparathyroidism and Papillary Thyroid Cancer-A Rare Case

The frequency of concurrent thyroid cancer in patients with primary hyperparathyroidism (pHPT) varies. While the pathological association between thyroid and parathyroid disorders is frequently noted, the co-occurrence of parathyroid adenoma and papillary thyroid cancer is exceptionally rare. Furthermore, an ectopic parathyroid adenoma in the retropharyngeal space is exceedingly rare. Therefore, anatomical variations through the utilization of relevant diagnostic tools play a crucial role in guiding decisions pertaining to clinical manifestations, diagnostic methods, surgical interventions, and operative strategies for parathyroid tumors. We present a case of a 51-year-old female patient with papillary thyroid carcinoma in the right thyroid lobe and an ectopic parathyroid adenoma in the retropharyngeal space confirmed through surgical intervention. The elevated preoperative levels of serum calcium and parathyroid hormone, along with low serum phosphate, returned to normal ranges after surgery. This case sheds light on the unusual occurrence of an ectopic parathyroid adenoma in the retropharyngeal region within a thyroid cancer patient, providing valuable insights into the realm of thyroid malignancies.

A contemporary analysis of the pre- and intraoperative recognition of multigland parathyroid disease

BACKGROUND

Despite advances in biochemical and radiological identification of parathyroid gland enlargement, primary hyperparathyroidism (PHPT) due to sporadic multigland parathyroid disease (MGPD) remains a perioperative diagnostic dilemma. Failure to recognise MGPD pre- or intraoperatively may negatively impact surgical cure rates and result in persistent PHPT and ongoing patient morbidity.

METHODS

We have conducted a comprehensive review of published literature in attempt to determine factors that could aid in reliably diagnosing sporadic MGPD pre- or intraoperatively. We discuss preoperative clinical features and examine pre- and intraoperative biochemical and imaging findings concentrating on those areas that give practicing surgeons and the wider multi-disciplinary endocrine team indications that a patient has MGDP. This could alter surgical strategy.

CONCLUSION

Biochemistry can provide diagnosis of PHPT but cannot reliably discriminate parathyroid pathology. Histopathology can aid diagnosis between MGPD and adenoma, but histological appearance can overlap. Multiple negative imaging modalities indicate that MGPD may be more likely than a single parathyroid adenoma, but the gold standard for diagnosis is still intraoperative identification during BNE. MGPD remains a difficult disease to both diagnose and treat.

Adrenal Incidentalomas and Other Endocrine-Related Adenomas: How Much Does Cortisol Secretion Matter?

Background: Adrenal incidentalomas (AI) are frequent findings in clinical practice. About 40% of AIs are associated with hypercortisolism of variable severity. Although mild autonomous cortisol secretion (MACS) has been associated with the impaired clinical outcome of several diseases, its effect on the development of benign neoplasms is unknown. Aim: To compare the prevalence of adenomas (thyroid, parathyroid, pituitary and other locations) in patients with nonfunctioning AIs (NFAIs) and MACS. Methods: A multicenter, retrospective study of patients with AIs evaluated in four tertiary hospitals was performed. Results: A total of 923 patients were included. Most patients were male (53.6%), with a mean age at diagnosis of 62.4 ± 11.13 years; 21.7% presented with bilateral AIs. MACS was observed in 29.9% (n = 276) of patients, while 69.9% (n = 647) were NFAIs. Adenomas in locations other than the adrenal gland were observed in 36% of the studied population, with a similar distribution in patients with MACS and NFAIs (33% vs. 32%; p > 0.05). There were no statistically significant differences in the prevalence of pituitary, thyroid, parathyroid or other endocrine-related adenomas between both groups, but the prevalence of metabolic comorbidities and mortality was increased in patients with MACS, specifically in patients with thyroid and other endocrine-related adenomas (p < 0.05). Conclusions: Adenomas in locations other than the adrenal glands occur in one third of patients with AIs. Mild autonomous hypercortisolism does not affect the prevalence of other endocrine-related adenomas but is associated with increased metabolic comorbidities and mortality, especially in patients with thyroid adenomas and adenomas in other locations.

Predicting multigland disease in primary hyperparathyroidism using ultrasound and clinical features

Background

The identification of multigland disease (MGD) in primary hyperparathyroidism (PHPT) patients is essential for minimally invasive surgical decision-making.

Objective

To develop a nomogram based on ultrasound (US) findings and clinical factors to predict MGD in PHPT patients.

Materials and methods

Patients with PHPT who had surgery between March 2021 and January 2022 were consecutively enrolled to this study. Biochemical and clinicopathological data were recorded. US images were analyzed to extract US features for prediction. Logistic regression analyses were used to identify MGD risk factors. A nomogram was constructed based on these factors and its performance evaluated by area under the receiver operating characteristic curve (AUC), calibration curve, Hosmer-Lemeshow tests, and decision curve analysis (DCA).

Results

A total of 102 PHPT patients were included; 82 (80.4%) had single-gland disease (SGD) and 20 (19.6%) had MGD. Using multivariate analyses, MGD was positively correlated with age (odds ratio (OR) = 1.033, 95% confidence interval (CI): 0.190-4.047), PTH levels (OR = 1.001, 95% CI: 1.000-1.002), multiple endocrine neoplasia type 1 (MEN1) (OR = 29.730, 95% CI: 3.089-836.785), US size (OR = 1.198, 95% CI: 0.647-2.088), and US texture (cystic-solid) (OR = 5.357, 95% CI: 0.499-62.912). MGD was negatively correlated with gender (OR = 0.985, 95% CI: 0.190-4.047), calcium levels (OR = 0.453, 95% CI: 0.070-2.448), and symptoms (yes) (OR = 0.935, 95% CI: 0.257-13.365). The nomogram showed good discrimination with an AUC = 0.77 (0.68-0.85) and good agreement in predicting MGD in PHPT patients. Also, 65 points was recommended as a cut-off value, with specificity = 0.94 and sensitivity = 0.50.

Conclusion

US was useful in evaluating MGD. Combining US and clinical features in a nomogram showed good diagnostic performance for predicting MGD.

Contribution of intraoperative parathyroid hormone monitoring to the surgical success in minimal invasive parathyroidectomy

Background

The contribution of intraoperative parathyroid hormone monitoring to minimally invasive parathyroidectomy remains controversial. We aimed to evaluate whether intraoperative parathyroid hormone monitoring monitoring could contribute to minimally invasive parathyroidectomy in these patients.

Methods

The data of the patients whose preoperative ultrasonography and technetium-99 m sestamibi scintigraphy imagings were positive and concordant for one gland and who underwent minimally invasive parathyroidectomy between 2003 and 2018 in our clinic, were evaluated retrospectively. Blood samples were collected at pre-excisional period, and at post-excisional 10 and 20 min; the intaoperative parathyroid hormone was measured, and the surgery was terminated without waiting for the result. Patients were divided into 2 groups according to the postoperative results, as those with normocalcemia (Group 1) and those with persistence (Group 2).

Results

There were 195 patients in Group 1 and 14 patients in Group 2. The cure rate at the first surgery was 93.3%. Cure was achieved after the second operation in all patients in Group 2. Recurrent disease developed in 1 patient in group 1 and the overall cure rate was 99.5%. If intraoperative parathyroid hormone had been evaluated, cure could have been achieved at the first surgery with additional exploration, in 10 (71.4%) of 14 patients according to the insufficient decrease in parathyroid hormone value at the 10 min in Group 2, and in 9 (64.3%) of 14 patients according to the parathyroid hormone value at 20 min. However, due to insufficient decrease (false negative) in the parathyroid hormone value at the 10 and 20 min the rate of false negatives and unnecessary exploration would be 9.5% and 2.5%, respectively. With additional exploration, the cure rate in the first surgery could be increased by 4.3%–97.6% according to the 20 min intraoperative parathyroid hormone value.

Conclusion

The cure rate in minimally invasive parathyroidectomy can be increased by minimizing unnecessary conversion to bilateral neck exploration, by evaluating intraoperative parathyroid hormone at 10 min in patients with positive and concordant scans, and intraoperative parathyroid hormone at 20 min in patients with inadequate decrease at 10 min intraoperative parathyroid hormone.

Primary hyperparathyroidism in pregnancy: experience of a tertiary centre

Background and purpose

The management of primary hyperparathyroidism (PHPT) during pregnancy is challenging and there is no clear consensus on whether it increases the risk of complications in pregnancy. We conducted this study to review the maternal and fetal outcomes of pregnant women treated for PHPT in a single centre.

Methods

Data on relevant clinical parameters, demographics, management strategies, maternal and fetal outcomes were collected from the medical records of pregnant patients with PHPT diagnosed between 2012 and 2019.

Results

Of 15 pregnant women with PHPT, 6 were managed medically and 9 underwent surgery. The median age at their index pregnancy was 28 years [range 19–42]. The median highest adjusted calcium level in the medical group was 2.90 [range 2.61–3.25] mmol/L vs. 3.11 [2.78–4.95] mmol/L in the surgical group. There was one miscarriage and the stillbirth of twins in the medical group, but no such outcomes in the surgical group. The median gestational ages were 39 + 3 weeks [range 24 + 2–41 + 2 weeks] and 39 + 4 weeks [range 37 + 1–39 + 5 weeks] in the medical and surgical groups, respectively. No birth was complicated by neonatal tetany or convulsions.

Conclusion

More complications developed in the pregnant PHPT patients who were managed medically than in those who underwent surgery. Surgery performed during the second trimester resulted in good outcomes. Multi-centre prospective studies are required to ascertain the risk of various complications in women with PHPT during pregnancy.

Multiglandular Parathyroid Disease

Introduction: Multiglandular parathyroid disease (MGD) is an uncommon cause of primary hyperparathyroidism (pHPT) and has been reported in the literature in 8–33% of patients with pHPT. The aim of our study was to review the clinical characteristics and management of MGD and evaluation of surgical treatment failures. Methods: We performed a retrospective study of 163 patients with pHPT undergoing parathyroidectomy (PTX) at the Department of General and Endocrine Surgery between 1983 and 2018. All these patients were diagnosed with MGD. This group of patients was compared with a group of 856 patients with solitary disease operated for pHPT in the same period. Results: Among 163 patients—127 (79%) of them had two lesions, 28 (16%) had three, and 8 (5%) four. They were prevalently women over the age of 50. The diagnosis was based on PTH and ionized calcium studies and used sestamibi technetium-99m scintigraphy (MIBI) as well for us. Treatment was surgical. Conclusions: Parathyroidectomy (PTX) for multiglandular parathyroid disease (MGD) is associated with a higher operative risk of failure compared to solitary disease. Preoperative diagnosis and localization of the parathyroid glands is an extremely important element of treatment. Diagnosis is based on PTH and calcium levels. Ultrasonography (USG), MRI, and scintigraphy are very helpful in diagnosis. Mediastinal multiglandular parathyroid disease (MGD) is associated with increased surgical treatment failures. The treatment is surgical and consists of the removal of the masses or complete parathyroidectomy. Based on this study, we support the existence of multiple adenomas and advocate the removal of only macroscopically enlarged parathyroid glands in patients with primary hyperparathyroidism.

Artificial intelligence-augmented, label-free molecular imaging method for tissue identification, cancer diagnosis, and cancer margin detection

Label-free high-resolution molecular and cellular imaging strategies for intraoperative use are much needed, but not yet available. To fill this void, we developed an artificial intelligence-augmented molecular vibrational imaging method that integrates label-free and subcellular-resolution coherent anti-stokes Raman scattering (CARS) imaging with real-time quantitative image analysis via deep learning (artificial intelligence-augmented CARS or iCARS). The aim of this study was to evaluate the capability of the iCARS system to identify and differentiate the parathyroid gland and recurrent laryngeal nerve (RLN) from surrounding tissues and detect cancer margins. This goal was successfully met.

Double ipsilateral parathyroid adenomas, with one supernumerary and ectopic at the same time: a case report

Background

Double adenomas (DA) represents a distinct clinical entity of primary hyperparathyroidism (PHPT). DA may follow various embryologic distribution patterns and could be supernumerary and/or ectopic.

Case presentation

We describe the first case of PHPT which comes as a result of double ipsilateral adenoma, of which one was both ectopic and supernumerary. A 45 year-old Greek male patient with diagnosed PHPT due to a single lower right parathyroid adenoma was admitted to our department for surgical treatment. The preoperative tests (neck US, Sestamibi scan) were conclusive for single gland disease. The patient underwent focused parathyroidectomy. The frozen section revealed a parathyroid adenoma with a slight possibility for parathyroid carcinoma. Ten minutes after the excision, intact PTH (iPTH) dropped >50% related to preoperative values and was within normal range. Right hemithyroidectomy with additional ipsilateral central neck dissection was performed, because of the possibility for parathyroid carcinoma. The final pathology report showed that the first excised tissue proved to be a parathyroid adenoma, while a second subcapsular one and a normal right upper parathyroid gland were also found.

Conclusions

Preoperative localization of DA using routine imaging tests and the utility of intraoperative parathyroid hormone assay are still unreliable in detecting multiple adenomas. Furthermore, a slight possibility of a second and simultaneously supernumerary and ectopic adenoma maybe present. Therefore, it would be advisable to establish the use of more advanced imaging tests (such as 4D-CT, 4D-MRI) or other diagnostic tools when DA are suspected.

Usefulness of the Wisconsin and CaPTHUS indices for predicting multiglandular disease in patients with primary hyperparathyroidism in a southern European population

Background

Focused parathyroidectomy is a safe technique for the treatment of primary hyperparathyroidism. The CaPTHUS score and the Wisconsin index are preoperative diagnostic tools designed to distinguish between single- and multigland disease. The aim of the study is to evaluate the usefulness of these models for predicting multiglandular disease in a European population.

Methods

Retrospective review of a database of patients operated upon for primary hyperparathyroidism at a referral center. The sensitivity, specificity, positive and negative predictive values, and reliability of both scores for the prediction of multiglandular disease, were calculated. Receiver operating characteristic (ROC) curves were constructed to assess the sensitivity and specificity of CaPTHUS score and Wisconsin Index for predicting single-gland disease. A level of P<0.05 was accepted as significant.

Results

Two hundred and eighty-one patients who underwent successful surgery from January 2001 to December 2018 were included. Single-gland disease was detected in 92.5%, and 73.7% had a CaPTHUS score of ≥3. The sensitivity, specificity, positive and negative predictive values of this model for predicting single-gland disease with a score of ≥3 were 76.9%, 66.7%, 96.6%, and 18.9% respectively. The area under the curve value of the CaPTHUS score for predicting single-gland disease was 0.74. A Wisconsin Index >2,000 and an excised gland weight above one gram presented a positive predictive value for single-gland disease of 92.5%.

Conclusions

Despite the good performance of both scales, the established cut-off points did not definitively rule out parathyroid multiglandular disease in our population. In cases with a minimal suspicion of this condition, additional intraoperative techniques must be used, or bilateral neck explorations should be performed.

Stepwise Approach for Parathyroid Localisation in Primary Hyperparathyroidism

INTRODUCTION

Primary hyperparathyroidism (PHPT) is a relatively common condition in surgical practice. Availability of localisation studies has shifted the treatment from bilateral neck exploration to selective parathyroidectomy. Several imaging modalities, each with varying sensitivities, are available to detect abnormal parathyroid glands. Ultrasound is almost universally accepted as the first line radiological investigation however its sensitivity is particularly heterogeneous and operator-dependent.

MATERIAL AND METHODS

We studied 250 consecutive patients with PHPT who underwent parathyroidectomy in our hospital over a period of 33 months. Pre-operative neck ultrasound, 99mTc-sestamibi and single-photon emission computed tomography (SPECT CT) were performed in 249, 237 and 198 patients respectively. Unilateral and bilateral neck exploration was performed in 190 and 60 patients, respectively. Sensitivity, positive predictive value (PPV) and accuracy were calculated comparing the results with surgical and pathology findings.

RESULTS

Mean pre and postoperative PTH and adjusted calcium were, 11 ± 10.6 pmol/L, 1.9 ± 3.6, 2.81 ± 0.2 and 2.45 ± 0.2 mmol/L. There were 71 (29.95%) discordant results between US, compared to sestamibi and SPECT CT. An average of 1.9 parathyroid glands were removed with a mean weight of 0.92 g. Overall success rate based on postoperative PTH levels was 94.8%. Overall sensitivity, PPV and accuracy for US were 80.80%, 92.35%, and 75.73% respectively; for sestamibi were 71.82%, 94.61%, 69.00% and for SPECT CT were; 70.21%, 97.78%, 69.11% respectively.

CONCLUSION

Ultrasound performed by an experienced specialist sonographer is highly sensitive in localising abnormal parathyroid glands. It can be used as a main and sole investigation in the majority of patients. Sestamibi, SPECT CT and other investigations should be performed in a step-wise manner and reserved for patients with negative US, failed primary procedure and recurrences.

Identification of key regulators in parathyroid adenoma using an integrative gene network analysis

Parathyroid adenoma (PA) is marked by a certain benign outgrowth in the surface of parathyroid glands. The transcriptome analysis of parathyroid adenomas can provide a deep insight into actively expressed genes and transcripts. Hence, we analyzed and compared the gene expression profiles of parathyroid adenomas and healthy parathyroid gland tissues from Gene Expression Omnibus (GEO) database. We identified a total of 280 differentially expressed genes (196 up-regulated, 84 down-regulated), which are involved in a wide array of biological processes. We further constructed a gene interaction network and analyzed its topological properties to know the network structure and its hidden mechanism. This will help to understand the molecular mechanisms underlying parathyroid adenoma development. We thus identified 13 key regulators (PRPF19, SMC3, POSTN, SNIP1, EBF1, MEIS2, PAX9, SCUBE2, WNT4, ARHGAP10, DOCK5, CAV1 and VSIR), which are deep-rooted from top to bottom in the gene interaction network forming a backbone for the network. The structural features of the network are probably maintained by crosstalk between important genes within the network along with associated functional modules.Thus, gene-expression profiling and network approach could be used to provide an independent platform to glen insights from available clinical data.

Intravagal parathyroid adenomas: Case report and literature review

Intravagal parathyroid adenomas remain an exceedingly rare diagnosis; however, their true incidence may be higher than currently known. It is important to keep intravagal sites within the list of potential ectopic locations of parathyroid adenomas.

Utility of a Second 99mTc-MIBI Scintigraphy Before Reoperation for Patients With Persistent Sporadic Primary Hyperparathyroidism: Results of a Retrospective Multicenter Study

BACKGROUND

Persistent primary hyperparathyroidism (PHPT) occurs in 2.5% to 15% of cases after parathyroidectomy. Few studies have evaluated the best pre-reoperative imaging approaches for persistent sporadic PHPT. This retrospective multicenter study aimed to evaluate the benefit of a second pre-reoperative ^99mTc-methoxy-isobutyl-isonitrile (MIBI) scintigraphy for patients with persistent PHPT who had a ^99mTc-MIBI before their initial surgery.

METHODS

The study enrolled 50 patients with persistent sporadic PHPT who had reoperation between 2006 and 2016 in three French University Hospitals (Angers, Nantes, and La Pitié Salpêtrière-Paris). Preoperative ^99mTc-MIBI scan was performed before each operation.

RESULTS

After the reoperation, 42 patients (84%) were cured. By the second ^99mTc-MIBI, 31 patients (62%) had a removed gland identified. A new pathologic gland was identified by a second ^99mTc-MIBI in 25 patients (50%), and this imaging permitted correction of an initial surgical error in six patients (12%). A second ^99mTc-MIBI showed a sensitivity of 63%, a specificity of 89%, a positive predictive value (PPV) of 78%, and a negative predictive value (NPV) of 80%. A concordant second ^99mTc-MIBI and ultrasonography (17 patients) showed a sensitivity of 70%, a specificity of 81%, a PPV of 70%, and an NPV of 81%.

CONCLUSIONS

Performing a second ^99mTc-MIBI scan permitted 62% of the persistent PHPT patients to be cured, allowing identification of new pathologic glands in 50% of the cases and correction of an initial surgical error in 12% of the cases, with high specificity and PPV. These results reinforce the fact that a second ^99mTc-MIBI scan should be performed at first intention before reoperation of patients with persistent PHPT, regardless of the result from the initial ^99mTc-MIBI scan.

The surgical management of sporadic primary hyperparathyroidism

Sporadic primary hyperparathyroidism (pHPT) is the commonest cause of hypercalcaemia in the ambulatory population. It has a female preponderance and its incidence is increasing. In 85% of cases it is caused by a single parathyroid adenoma, with four gland hyperplasia in up to 20%. Parathyroidectomy is the only cure and bilateral neck exploration remains the gold standard to achieve this. Several adjuncts have been developed to improve success rates or limit the extent of surgery. Pre-operative localisation permits planned targeted surgery. Ultrasound scanning and scintigraphy are the most commonly employed, although 4DCT has become a useful modality in complex cases. However, excellent rates of biochemical cure can be achieved in specialist centres when pre-operative imaging is negative. Pre-operative prediction models and intra-operative parathyroid hormone (ioPTH) assist, with high sensitivity, to predict single gland disease. Reoperations present a major challenge to the endocrine surgeon.