The prevalence and anatomy of parathyroid glands: a meta-analysis with implications for parathyroid surgery

Association of primary hyperparathyroidism with pituitary adenoma and management issues

The co-occurrence of primary hyperparathyroidism (PHPT) and pituitary adenomas (PAs) is often indicative of underlying genetic syndromes such as Multiple Endocrine Neoplasia type 1 (MEN1) and, less commonly, MEN4. Although both conditions can occur sporadically, their simultaneous presence warrants evaluation for genetic mutations, with MEN1 mutations being the most frequent cause. The management of concurrent PHPT and PAs, especially in MEN1 patients, presents unique challenges. Management complexities arise from the syndromic nature, involving both surgical and medical interventions tailored to each condition. PHPT often manifests earlier and more aggressively in MEN1, requiring surgical intervention. However, recurrence rates remain high due to multiglandular involvement. Pituitary adenomas in MEN1 are primarily prolactinomas, and treatment with dopamine agonists results in significant tumour control in most cases. Overall, PAs associated with MEN1 are generally responsive to medical therapy, but careful long-term monitoring is essential. The utility of genetic screening cannot be overstated, as it aids in early detection, risk stratification, and management of both the index case and affected family members by cascade screening. A multidisciplinary approach is crucial for optimizing outcomes, with ongoing surveillance to manage recurrence and associated complications. In summary, the co-occurrence of PHPT and PAs, particularly in the context of MEN1, necessitates an integrated management strategy. Genetic testing is key in confirming diagnosis and guiding treatment, while surgical and medical interventions should be tailored to the extent and nature of glandular involvement. Close monitoring for recurrence and proactive family screening are essential components of long-term care.

The polar vessel sign: insights from CT imaging analysis in Asian Indian primary hyperparathyroidism

PURPOSE

Data on the polar vessel sign (enlarged feeding vessel terminating in parathyroid lesions) on four-dimensional computed tomography (4D-CT) is limited. We performed a retrospective analysis to determine the prevalence, predictors, and adjunctive utility of polar vessel sign in pre-operative 4D-CT of patients with primary hyperparathyroidism (PHPT).

METHODS

One radiologist blinded to the patients' details reported the 4D-CT of eighty-four operated patients with histopathology-proven single-gland PHPT. Two protocols were used to obtain arterial-phase images: timed via bolus tracking (n = 41) or fixed at 20 s after contrast injection (n = 43).

RESULTS

Seventy-one patients were symptomatic for PHPT, with median serum calcium 12.1 mg/dL. On the arterial phase of 4D-CT, 88.1% of lesions had the polar vessel sign, including 7/9 asymptomatic patients, 6/6 parathyroid carcinomas, and 3/4 ectopic(1:mediastinum, 2:thyro-thymic ligament). Predictors of polar vessel sign were maximum lesion dimension (2.2 vs. 1.4 cm; P = 0.03), solid-cystic CT morphology (47.3% vs. none; P = 0.004), and bolus tracking-timed arterial phase (55.4% vs. none; P = 0.001). Of these, bolus tracking improved the polar vessel's visualization (100% vs. 76.7%; P = 0.001) independent of lesion dimension and solid-cystic morphology. The latter two predicted polar vessel sign in images obtained at a fixed interval (20 s). A significantly lower proportion of bolus tracking-timed scans had lesion percentage arterial enhancement (PAE) < 128.9% (2/41 vs. 9/43; P = 0.04). Even with suboptimal PAE, the polar vessel helped identify 9/11 lesions.

CONCLUSION

The polar vessel sign demonstrated an additive role to PAE during CT reporting. Bolus tracking is valuable in optimizing vessel and tumor arterial enhancement and is easily incorporated into parathyroid 4D-CT protocol.

Robotic transthoracic approach to ectopic mediastinal parathyroid adenoma: A case report

INTRODUCTION

Ectopic parathyroid adenomas represent an important cause of refractory hyperparathyroidism. While most ectopic mediastinal parathyroid adenomas can be accessed through a transcervical approach, this is not always feasible, posing a significant challenge.

CASE PRESENTATION

We report the case of a 60-year-old female patient who presented with symptomatic hyperparathyroidism. Sestamibi scan was performed and failed to identify a parathyroid adenoma. Bilateral neck exploration was performed on twice, with normal parathyroid glands excised on both occasions. At this stage, a repeat sestamibi and CT scan revealed a suspected parathyroid adenoma in the mediastinum. A transthoracic robotic parathyroidectomy was performed, and the adenoma successfully excised. A full serological and symptomatic recovery was achieved.

DISCUSSION

Mediastinal parathyroid adenomas can pose significant diagnostic and treatment challenges.

CONCLUSION

A robotic transthoracic approach demonstrates a safe method for the removal of parathyroid adenomas which are inaccessible transcervically, with low morbidity to patients.

Exploring near-infrared autofluorescence properties in parathyroid tissue: an analysis of fresh and paraffin-embedded thyroidectomy specimens

Significance

Near-infrared autofluorescence (NIRAF) utilizes the natural autofluorescence of parathyroid glands (PGs) to improve their identification during thyroid surgeries, reducing the risk of inadvertent removal and subsequent complications such as hypoparathyroidism. This study evaluates NIRAF's effectiveness in real-world surgical settings, highlighting its potential to enhance surgical outcomes and patient safety.

Aim

We evaluate the effectiveness of NIRAF in detecting PGs during thyroidectomy and central neck dissection and investigate autofluorescence characteristics in both fresh and paraffin-embedded tissues.

Approach

We included 101 patients diagnosed with papillary thyroid cancer who underwent surgeries in 2022 and 2023. We assessed NIRAF's ability to locate PGs, confirmed via parathyroid hormone assays, and involved both junior and senior surgeons. We measured the accuracy, speed, and agreement levels of each method and analyzed autofluorescence persistence and variation over 10 years, alongside the expression of calcium-sensing receptor (CaSR) and vitamin D.

Results

NIRAF demonstrated a sensitivity of 89.5% and a negative predictive value of 89.1%. However, its specificity and positive predictive value (PPV) were 61.2% and 62.3%, respectively, which are considered lower. The kappa statistic indicated moderate to substantial agreement (kappa = 0.478; P < 0.001 ). Senior surgeons achieved high specificity (86.2%) and PPV (85.3%), with substantial agreement (kappa = 0.847; P < 0.001 ). In contrast, junior surgeons displayed the lowest kappa statistic among the groups, indicating minimal agreement (kappa = 0.381; P < 0.001 ). Common errors in NIRAF included interference from brown fat and eschar. In addition, paraffin-embedded samples retained stable autofluorescence over 10 years, showing no significant correlation with CaSR and vitamin D levels.

Conclusions

NIRAF is useful for PG identification in thyroid and neck surgeries, enhancing efficiency and reducing inadvertent PG removals. The stability of autofluorescence in paraffin samples suggests its long-term viability, with false positives providing insights for further improvements in NIRAF technology.

18F-Fluorocholine-Positron Emission Tomography/Computerized Tomography (FCH PET/CT) Imaging for Detecting Abnormal Parathyroid Glands: Indication, Practice, Interpretation and Diagnostic Performance

In patients with confirmed hyperparathyroidism (HPT) scheduled for surgical treatment, the preoperatory imaging permits to optimize the operatory protocol of parathyroidectomy (PTX), in particular by selecting those patients who can benefit from minimally invasive PTX (MIPTX). The MIPTX has the merit to shorten the operative time, incision length, and to reduce the operatory risks. With preoperative localization studies, the rate of PTX failure, in particular due to nonsuspected multiglandular or ectopic disease, has been profoundly decreased. The first cases of incidental localization of abnormal parathyroid glands (PTs) on FCH PET/CTs performed for another indication were reported more than one decade ago. Since then, significant amount of data from heterogeneous series of patients consistently confirmed better diagnostic performances of FCH PET/CT (sensitivity for detection of abnormal PT 97%, range 96%-98%) in comparison with other radiopharmaceuticals, ultrasonography or 4D-CeCT in localizing hyperfunctioning parathyroid glands (HFPTGs) in case of primary HPT. Utility of FCH PET/CT in case of renal HPT has been reported in fewer series. The article discusses and summarizes the bibliographic evidence on documented indications of FCH PET/CT in patients with HPT, its safety profile, the practice of FCH PET/CT and interpretation of FCH PET/CT findings, including potential interpretation pitfalls and tips to avoid them. Our real-world experience over 12 years reinforces published evidence supporting the use of FCH PET/CT as the first-line radionuclide imaging technique in patients with all types of HPT in whom surgery is an option.

Giant Parathyroid Adenoma of the Posterior Mediastinum

Ectopic parathyroid adenoma is a rare pathology. We present a clinical case of a giant ectopic parathyroid adenoma (PA) in an unusual location, which brought significant diagnostical and therapeutical challenges. The tumour in the mediastinum was found incidentally on chest computed tomography (CT). A biopsy was conducted, and histological examination revealed a well-differentiated neuroendocrine tumour. The tumour was excised via right thoracotomy. The final histological examination revealed a parathyroid adenoma, which was unexpected for our team. After three years of observation, there is no evidence of tumour recurrence.

Addressing the challenges of missed parathyroid glands in ultrasonography for secondary hyperparathyroidism: a retrospective observational study

Purpose

Preoperative localization plays an important role in secondary hyperparathyroidism (SHPT) surgery. The advantages of neck ultrasound (US) include high availability and low cost. However, the reported sensitivity of US is 54%-76%, and the reason for missed parathyroid glands (PGs) on US has been rarely addressed.

Methods

Fifty-four patients who were diagnosed with renal SHPT from September 2020 to March 2022 were included in this retrospective study. Preoperative localization included surgeon-oriented US and technetium 99m-sestamibi single-photon emission CT (SPECT)/CT.

Results

A total of 212 PGs were pathologically confirmed, resulting in a success rate of 96.2% (52 of 54). Using echo, 193 PGs (91.0%) were accurately localized, while 19 glands (9.0%) were not identified, including those in ectopic positions (n = 12, at thymus or intrathyroid or others), of small size (<1 cm, n = 6), or overlapping with an ipsilateral PG (n = 1). US accurately detected 4 PGs in 36 (66.7%) patients, while SPECT/CT localized 4 glands in 19 patients (35.2%). Although the number of US-detectable PGs was not associated with success rate, it showed a significant negative correlation with surgical time (rs = -0.459, P = 0.002).

Conclusion

US detected 4 glands in 66% of SHPT patients with a sensitivity of 90% for localization. Ectopic position and small size were the most common reasons for the failure to detect PG on US. Complete preoperative echo localization might shorten operating time.

Imaging Recommendations for Diagnosis and Management of Primary Parathyroid Pathologies: A Comprehensive Review

Parathyroid pathologies are suspected based on the biochemical alterations and clinical manifestations, and the predominant roles of imaging in primary hyperparathyroidism are localisation of tumour within parathyroid glands, surgical planning, and to look for any ectopic parathyroid tissue in the setting of recurrent disease. This article provides a comprehensive review of embryology and anatomical variations of parathyroid glands and their clinical relevance, surgical anatomy of parathyroid glands, differentiation between multiglandular parathyroid disease, solitary adenoma, atypical parathyroid tumour, and parathyroid carcinoma. The roles, advantages and limitations of ultrasound, four-dimensional computed tomography (4DCT), radiolabelled technetium-99 (99mTc) sestamibi or dual tracer 99mTc pertechnetate and 99mTc-sestamibi with or without single photon emission computed tomography (SPECT) or SPECT/CT, dynamic enhanced magnetic resonance imaging (4DMRI), and fluoro-choline positron emission tomography (18F-FCH PET) or [11C] Methionine (11C -MET) PET in the management of parathyroid lesions have been extensively discussed in this article. The role of fluorodeoxyglucose PET (FDG-PET) has also been elucidated in this article. Management guidelines for parathyroid carcinoma proposed by the American Society of Clinical Oncology (ASCO) have also been described. An algorithm for management of parathyroid lesions has been provided at the end to serve as a quick reference guide for radiologists, clinicians and surgeons.

Dual-tracer subtraction scintigraphy combined with SPECT/CT in preoperative patients with primary hyperparathyroidism

Abstract.

[Management of primary hyperparathyroidism with rare localization of ectopic adenoma parathyroid gland]

Topical diagnosis can be severely complicated in patients with primary hyperparathyroidism (PHPT) due to the ectopic placement of parathyroid gland (PTG) formations. We report a clinical case of PHPT in an 84-year-old patient caused by ectopic PTG adenoma located behind the right internal jugular vein at the level of the right submandibular gland. The impossibility of surgery for a long time due to the absence of a topical diagnosis has necessitated conservative treatment was required to get the hypercalcemia under control. In view of the concomitant deficiency of vitamin D, an attempt was made to use therapy with saturating doses of cholecalciferol under dynamic monitoring of the indicators of phosphorus-calcium metabolism, which allowed to achieve a significant decrease in PTH levels while maintaining normocalcemia.

The Parathyroid Gland: An Overall Review of the Hidden Organ for Radiologists

Parathyroid glands are small endocrine glands that regulate calcium metabolism by producing parathyroid hormone (PTH). These are located at the back of the thyroid gland. Typically, four glands comprise the parathyroid glands, although their numbers may vary among individuals. Parathyroid diseases are related to parathyroid gland dysfunction and can be caused by problems with the parathyroid gland itself or abnormal serum calcium levels arising from renal disease. In recent years, as comprehensive health checkups have become more common, abnormal serum calcium levels are often found incidentally in blood tests, after which several additional tests, including a PTH test, ultrasonography (US), technetium-99m sestamibi parathyroid scan, single-photon-emission CT (SPECT)/CT, four-dimensional CT (4D-CT), and PET/CT, are performed for further evaluation. However, the parathyroid gland remains an organ less familiar to radiologists. Therefore, the normal anatomy, pathophysiology, imaging, and clinical findings of the parathyroid gland and its associated diseases are discussed here.

Myopathies of endocrine origin: A review for physicians

Myopathies are a common manifestation of endocrine disorders. Endocrine myopathies are often overlooked while considering differential diagnoses in patients with musculoskeletal symptoms. The hindrance to mobility and the musculoskeletal discomfort owing to these myopathies are important causes of disability and depreciated quality of life in these patients. Endocrine myopathies occur due to the effects of endogenous or iatrogenic hormonal imbalance on skeletal muscle protein and glucose metabolism, disrupting the excitation-contraction coupling. Abnormalities of the pituitary, thyroid, parathyroid, adrenal, and gonadal hormones have all been associated with myopathies and musculoskeletal symptoms. Endocrine myopathies can either be the complication of a secondary endocrine disorder or a presenting symptom of a missed underlying disorder. Therefore, an underlying endocrine abnormality must always be excluded in all patients with musculoskeletal symptoms. This review presents a compilation of various endocrine myopathies, their etiopathogenesis, clinical presentation, diagnostic modalities, and treatment protocols.

Brown tumor due to primary hyperparathyroidism in a familial case: a case report

BACKGROUND

Primary hyperparathyroidism (PHPT) is an uncommon disorder characterised by hypercalcemia with an increased parathyroid hormone level. We reported a PHPT familial case with two subjects, a father and a daughter, and both of them had suffered from the brown tumor.

CASE PRESENTATION

The proband, a 43-year-old patient, developed parathyroid adenomas at the age of 15; a histologically confirmed right parathyroid adenoma was removed by parathyroidectomy; and after six months follow-up, the serum calcium level was normalised. At the age of thirty-three, a CT scan of his head and neck revealed a mass in the right maxilla, as well as PHPT (i.e., left inferior parathyroid adenoma). Then, he underwent a biopsy of an exophytic lesion in the right maxilla and was diagnosed by pathology as a brown tumor, with the serum calcium and PTH levels at 2.78 mmol/L and 221 pg/mL, respectively. Subsequently, the patient took a left inferior parathyroid microwave ablation with ultrasound guidance. After three months of follow-up, the serum calcium and PTH levels returned to normal, and the brown tumor was resolved. After three years, it mineralised as revealed in a CT scan. By the time he was 43 years old, during the 28-year follow-up period, the serum calcium and PTH levels were still within the normal range, and there was no discomfort reported. He has consistently taken calcium supplements throughout the 28 years. Since the initial diagnosis, his blood indicators of kidney function have been normal, and ultrasound showed renal calculus in the right kidney and a normal left kidney. The proband's daughter, a 15-year-old girl, experienced left upper extremity pain for ten months. CT scan revealed a mass in the distal left radius, and a giant cell tumor was suspected. A surgical internal fixation was performed, and the pathology showed a brown tumor. Laboratory tests revealed a serum parathyroid hormone (PTH) level of 1554pg/mL, calcium level of 3.14 mmol/L, phosphorus level of 0.72 mmol/L, and alkaline phosphatase level of 1892 U/L. Given the osteitic changes and elevated levels of calcium and PTH, ultrasonography was performed, after which a mass was detected measuring 19 × 9 × 7 mm mixed with solid components and cystic fluid in the right thyroid gland. The results of 99mTc-MIBI scintigraphy confirmed the abnormal accumulation of 99mTc-MIBI in the right thyroid gland but not seen in the bilateral parathyroid glands. The patient underwent thyroidectomy, and the postoperative pathology report indicated an intra-thyroid ectopic parathyroid adenoma. The serum calcium and PTH levels became normal at 4 h after surgery. One to three months after operation, the serum calcium level was low, while the serum PTH level was high. Then, the patient was advised to take calcium supplements. Until the sixth month after the operation, the serum calcium level and serum PTH level returned to normal, and the bone pain was relieved. The patient's blood tests for kidney function remained normal. There was no evidence of bilateral kidney disease (such as nephrolithiasis or nephrocalcinosis) detected by ultrasound scan. There were several similarities in the state of illness between these two subjects. Both the father and the daughter developed parathyroid adenomas at the age of 15, and there was no lesion in other endocrine glands. And genetic testing revealed mutations in the CDC73 genes in both father and daughter. On the other hand, there were also a few differences. The father's first signs of brown tumor were in the right maxilla, while the daughter's appeared in the distal left radius. The father presented pathological changes in the left and right parathyroid glands, whereas the daughter presented with an ectopic parathyroid adenoma in the right thyroid gland.

CONCLUSION

We report a familial case in which father and daughter were diagnosed to have brown tumors due to parathyroid adenoma and ectopic parathyroid adenoma, and genetic testing revealed CDC73 gene mutations in both. Therefore, in the diagnostic and differential process of young patients having bone disease, clinicians should not only focus on the clinical manifestations of the skeleton, but also implement a comprehensive analysis of systemic symptoms, considering the possibility that the patient has familial PHPT.

Selective venous sampling in primary hyperparathyroidism caused by ectopic parathyroid gland: a case report and literature review

BACKGROUND

As an invasive technique, selective venous sampling (SVS) is considered a useful method to identify a lesion's location to increase the success rate of secondary surgery in patients with primary hyperparathyroidism (pHPT) caused by ectopic parathyroid adenomas.

CASE PRESENTATION

We present a case of post-surgical persistent hypercalcemia and elevated parathyroid hormone (PTH) levels in a 44-year-old woman with previously undetected parathyroid adenoma. An SVS was then performed for further localization of the adenoma, as other non-invasive methods showed negative results. After SVS, an ectopic adenoma was suspected in the sheath of the left carotid artery, previously considered as a schwannoma, and was pathologically confirmed after the second operation. Postoperatively, the patient's symptoms disappeared and serum levels of PTH and calcium normalized.

CONCLUSIONS

SVS can provide precise diagnosis and accurate positioning before re-operation in patients with pHPT.

Parathyroid Imaging

Primary hyperparathyroidism (1° HPT) is a relatively common endocrine disorder usually caused by autonomous secretion of parathormone by one or several parathyroid adenomas. 1° HPT causing hypercalcemia, kidney stones and/or osteoporosis should be treated whenever possible by parathyroidectomy. Accurate preoperative location of parathyroid adenomas is crucial for surgery planning, mostly when performing minimally invasive surgery. Cervical ultrasonography (US) is usually performed to localize parathyroid adenomas as a first intention, followed by 99mTc- sestamibi scintigraphy with SPECT/CT whenever possible. 4D-CT is a possible alternative to 99mTc- sestamibi scintigraphy. Recently, 18F-fluorocholine positron emission tomography/computed tomography (18F-FCH PET/CT) has made its way in the clinics as it is the most sensitive method for parathyroid adenoma detection. It can eventually be combined to 4D-CT to increase its diagnostic performance, although this results in higher dose exposure to the patient. Other forms of hyperparathyroidism consist in secondary (2° HPT) and tertiary hyperparathyroidism (3° HPT). As parathyroidectomy is not usually part of the management of patients with 2° HPT, parathyroid imaging is not routinely performed in these patients. In patients with 3° HPT, total or subtotal parathyroidectomy is often performed. Localization of hyperfunctional glands is an important aid to surgery planning. As 18F-FCH PET/CT is the most sensitive modality in multigland disease, it is the preferred imaging technic in 3° HPT patients, although its cost and availability may limit its widespread use in this setting.

Persistent and Recurrent Primary Hyperparathyroidism: Intraoperative Supplemental Methods, Basic Principles of Surgery, and Other Treatment Options

Reoperative parathyroid surgery is challenging even for experienced surgeons. Cure rates are lower than primary surgery. Good anatomical and embryological knowledge is important. Preoperatively, a comprehensive surgical strategy should be planned. Pre-operative imaging modalities should be used extensively to find the overlooked gland to have a possibility to perform focused parathyroid surgery to avoid possible complications. One of the important developments is the new ancillary methods to find overlooked parathyroid glands. Orthotopic and possible ectopic locations should be known well by the surgeon to increase the surgical success rate. Reoperative parathyroid surgery needs a distinctive approach compared to primary parathyroid surgery. Basic principles include the selection of the incision and route for entering the thyroid region, use of ancillary methods, and intraoperative nerve monitoring and also require a meticulous dissection. Obtaining a surgical cure is difficult and high surgical caution is needed. Post-operative complication rates are higher compared to primary parathyroid surgery. Other treatment methods and medical treatment options may be evaluated in a patient who cannot undergo surgery.

Mediastinal parathyroid carcinoma: a case report and review of the literature

BACKGROUND

Parathyroid carcinoma (PC) is an uncommon cause of primary hyperparathyroidism (PHPT) and particularly rare in the mediastinum. Herein, we present a case of mediastinal PC and conduct a related literature review.

CASE PRESENTATION

We described a case of a 50-year-old female patient with PHPT due to mediastinal PC. She was initially admitted to a local hospital in her hometown with hypercalcemia and high blood concentrations of PTH (parathyroid hormone). The patient underwent neck parathyroidectomy and pathological examination suggested parathyroid adenoma. Although the overproduction of serum calcium and PTH declined after the surgery, calcium and PTH increased again one month later, so the patient was transferred to our hospital. A 99^mTc-sestamibi scan revealed an ectopic finding in the mediastinum, which was also indicated on the CT image. After removing the mediastinal mass, the metabolism of calcium and PTH quickly reverted to normal and the pathologic features of the mass were consistent with PC. By reviewing the related literature, we noticed that only scattered reports were published before 1982, and those were not included in the present review due to their differences with current radiological examination and treatment methods. After excluding outdated studies, we summarized and analyzed 20 reports of isolated mediastinal PC and concluded that. Parathyroidectomy remains the only curative treatment for the disease. Furthermore, the success of treatment directly depends on accurate preoperative localization.

CONCLUSION

With this study, we emphasize the importance of accurate preoperative diagnosis of mediastinal PC and improve clinicians' understanding of the disease.

An Assessment of Enhancement Patterns in Abnormal Parathyroid Glands on Three-Phase CT Imaging

Background Four-dimensional computed tomography (4DCT) is increasingly used in the investigation of primary hyperparathyroidism. The objective of this study was to identify and analyse the usefulness of different enhancement patterns on 4DCT to improve its sensitivity. Methodology Retrospective data were collected on 100 glands. A consultant head and neck radiologist measured the Hounsfield units (HU) of the parathyroid gland and surrounding normal thyroid tissue in the pre-contrast, arterial and venous phases. Each gland was grouped according to the enhancement pattern, and the percentage change in HU was also calculated between the three phases. Results Thirty-five parathyroid glands demonstrated enhancement higher than the thyroid gland in the arterial phase and lower in the delayed phase and were placed into group A. Four parathyroid glands demonstrated enhancement higher than the thyroid gland in the arterial phase and also higher in the delayed phase and were placed into group B. Fifty-nine parathyroid glands demonstrated enhancement lower than the thyroid gland in the arterial phase and also lower in the delayed phase and were placed into group C. Two parathyroid glands demonstrated enhancement lower than the thyroid gland in the arterial phase and higher in the delayed phase and were placed into group D. Conclusions This study demonstrated that the classically described enhancement pattern of the parathyroid gland is not always present or the most frequent, thereby showing that the enhancement pattern cannot be relied upon in isolation. Instead, a thorough understanding of anatomy, embryology and possible ectopic gland locations is essential.

Preservation of parathyroid glands during thyroid and neck surgery

The parathyroid glands are situated in close proximity to the thyroid gland. They have an important endocrine function maintaining calcium and phosphate homeostasis in the body by the secretion of parathormone (PTH), which is responsible for this function. The parathyroid glands are commonly damaged during thyroid surgeries. This could lead to transient or permanent hypoparathyroidism in 30% of cases. Preservation of the parathyroid glands, is an important and integral part of thyroidectomy and other surgical interventions in the neck. The main principle underlying this is a thorough understanding of parathyroid anatomy in relation to the thyroid gland and other important structures in the area. There can also be significant variation in the anatomical location of the glands. Various techniques and methods have been described for parathyroid preservation. They include intraoperative identification utilizing indocyanine green (ICG) fluorescence, carbon nanoparticles, loupes, and microscopes. The techniques of surgery (meticulous capsular dissection), expertise, central compartment neck dissection, preoperative vitamin D deficiency, extent and type of thyroidectomy are the risk factors associated with damaged thyroids, inadvertent parathyroidectomy and subsequent hypoparathyroidism. Parathyroid Autotransplantation is a treatment option for inadvertent parathyroidectomy. Ultimately, the best way to assure normal parathyroid function is to preserve them in situ intraoperatively undamaged.

[Localization diagnostics and operative strategy for the first intervention in sporadic primary hyperparathyroidism]

Primary hyperparathyroidism (pHPT) is a frequent endocrine disease, the incidence of which is clearly increasing. In addition to the classical symptoms of bone pain, osteoporosis and renal calculi, nonspecific complaints, such as listlessness and exhaustion, anxiety states and depressive symptoms also often occur. The diagnosis is simple and is carried out by determination of calcium and parathormone (PTH) serum levels. The majority of parathyroid adenomas can be localized by ultrasound and Tc-99m-MIBI scintigraphy. The indications for surgery can normally already be identified by the laboratory biochemical detection. Surgery is the only curative treatment of pHPT and is normally successful. In addition to bilateral exploration, a focused parathyroidectomy can be planned. The success of surgery can be intraoperatively documented by the determination of intraoperative Quick PTH (IOPTH).

18F-Fluorocholine PET/CT Compared with Current Imaging Procedures for Preoperative Localization of Hyperfunctioning Parathyroids in Patients with Chronic Kidney Disease

Hyperparathyroidism (HPT) in patients with chronic kidney disease (CKD) includes secondary (sHPT) and tertiary hyperparathyroidism (tHPT). Considering that the role of preoperative imaging in the clinical setting is controversial, in the present study we have retrospectively compared pre-surgical diagnostic performances of ¹⁸F-Fluorocholine (¹⁸F-FCH) PET/CT, cervical ultrasonography (US), parathyroid scintigraphy, and 4D-CT in a group of 30 patients with CKD and HPT (18/12 sHPT/tHPT), 21 CKD G5 including 18 in dialysis, and 9 kidney transplant recipients. All patients underwent ¹⁸F-FCH, and 22 had cervical US, 12 had parathyroid scintigraphy, and 11 had 4D-CT. Histopathology was the gold standard. Seventy-four parathyroids were removed: 65 hyperplasia, 6 adenomas, and 3 normal glands. In the whole population, in a per gland analysis, ¹⁸F-FCH PET/CT was significantly more sensitive and accurate (72%, 71%) than neck US (25%, 43%), parathyroid scintigraphy (35%, 47%), and 4D-CT (40%, 47%). The specificity of ¹⁸F-FCH PET/CT (69%) was lower than that of neck US (95%) and parathyroid scintigraphy (90%), without, however, achieving significance. ¹⁸F-FCH PET/CT was more accurate than all other diagnostic techniques when sHPT and tHPT patients were considered separately. ¹⁸F-FCH PET/CT sensitivity was significantly higher in tHPT (88%) than in sHPT (66%). Three ectopic hyperfunctioning glands (in three different patients) were all detected by ¹⁸F-FCH PET/CT, two by parathyroid scintigraphy, and none by cervical US and 4D-CT. Our study confirms that ¹⁸F-FCH PET/CT is an effective preoperative imaging option in patients with CKD and HPT. These findings may be of greater importance in patients with tHPT (who could benefit from minimally invasive parathyroidectomy) than in patients with sHPT, who often undergo bilateral cervicotomy. In these cases, preoperative ¹⁸F-FCH PET/CT may be helpful in locating ectopic glands and may guide the surgical choice for gland preservation.

[Prediction model of recurrence after parathyroidectomy in secondary hyperparathyroidism]

Objective:To quantitatively evaluate the risk of recurrence in patients with secondary hyperparathyroidism after parathyroidectomy. Methods:The clinical data of 168 patients who underwent parathyroidectomy（PTX） from June 2017 to May 2019 were collected. The prediction model was constructed by using Akaike information criterion（AIC） to screen factors. A total of 158 patients treated with PTX from June 2019 to September 2021 were included in the validation set to conduct external validation of the model in three aspects of differentiation, consistency and clinical utility. Results:The prediction model we constructed includes different dialysis methods, ectopic parathyroid gland, the iPTH level at one day and one month after surgery, the number of excisional parathyroid and postoperative blood phosphorus. The C index of external validation of this model is 0.992 and the P value of the Calibration curve is 0.886[KG0.5mm]1. The decision curve analysis also shows that the evaluation effect of this model is perfect. Conclusion:The prediction model constructed in this study is useful for individualized prediction of recurrence after PTX in patients with secondary hyperparathyroidism.

The Dark Side of Ultrasound Imaging in Parathyroid Disease

The diagnosis of parathyroid diseases by imaging still has some intrinsic technical limitations due to the differential diagnosis of different structures of the neck that mimic the parathyroid glands. In this view, ultrasound (US) is an established, low-cost, and non-invasive imaging technique that still represents the first-line approach for evaluating patients with parathyroid disease. The objective of this article is to provide a comprehensive review of the applications of USs in clinical practice, discussing the histopathological and US characteristics of the parathyroid glands in normal and pathological conditions, the advantages of preoperative imaging, and novel updates on the most useful and currently available multiparameter US techniques.

Hyperparathyroidism: Pathological Diagnosis and Association with Parathyroid Localization

Background

The most comon patohistological finding in primary hyperparathyroidism is adenoma of the parathyroid gland, followed by hyperplasia and the rarest is carcinoma. However, hyperplasia of the parathyroid glands (PTG) is most commonly found in secondary and tertiary hyperparathyroidism.

Objective

To determine the relationship between the localization of the parathyroid glands and pathological diagnosis, as well as the prevalence of individual pathological diagnosis after surgery in patients with hyperparathyroidism.

Methods

Analysis of retrospective-prospective database of 79 patiens who underwent parathyreoidectomy for hyperparathyroidism in the 7-year study period. Diagnostic methods were used to identify enlarged parathyroid glands as well as to determine their localization: ultrasound examination, scintigraphy and operative finding. Standard hematoxylin eosin staining was used for pathohistological diagnosis. A correlation analysis between parathyroid gland localization and pathohistological diagnosis was performed.

Results

The median age of the patients were 51 age (range 20-73) and 67,1% of the patients were female. In the total number of surgically removed parathyroid glands (182), the most common pathohistological diagnosis was hyperplasia. Parathyroid adenoma was found in 21 cases. Other diagnoses (thyroid nodule / tissue, lymph node, thymus, cancer) were found in 11 cases, while a normal finding was found in 12 glands. Pathohistological diagnosis of hyperplasia and adenoma were more common in the lower parathyroid glands. Using the chi-square test, no association was found between pathohistological diagnosis and localization of enlarged parathyroid glands.

Conclusion

The most common pathohistological diagnosis in hyperparathyroidism was hyperplasia and was most commonly found in the inferior parathyroid glands. Adenoma as pathohistological diagnosis is also most commonly found in the lower parathyroid glands, but without statistical significance.

Persistent and Recurrent Primary Hyperparathyroidism: Etiological Factors and Pre-Operative Evaluation

Primary hyperparathyroidism (pHPT) is the most common cause of hypercalcemia and currently the only definitive treatment is surgery. Although the success rate of parathyroidectomy is over 95% in experienced centers, surgical failure is the most common complication today. Persistent HPT (perHPT) is defined as persistence of hypercalcemia after parathyroidectomy or recurrence of hypercalcemia within the first 6 months, and recurrence of hypercalcemia after a normocalcemic period of more than 6 months is defined as recurrent HPT (recHPT). In the literature, perHPT is reported to be 2-22%, and the rate of recHPT is 1-15%. perHPT is often associated with misdiagnosed pathology or inadequate resection of hyperfunctioning parathyroid tissue, recHPT is associated with newly developing pathology from potentially pathologically natural tissue left in situ at the initial surgery. In the pre-operative evaluation, the initial diagnosis of pHPT and the diagnosis of perHPT or rec HPT should be confirmed in patients who are evaluated with a pre-diagnosis (suspect) of perHPT and recHPT. Surgery is recommended if it meets any of the recommendations in surgical guidelines, as in patients with pHPT, and there are no surgical contraindications. The first preoperative localization studies, surgical notes, operation drawings, if any, intraoperative PTH results, pathological results, and post-operative biochemical results of these patients should be examined. Localization studies with preoperative imaging methods should be performed in all patients with perHPT and recHPT with a confirmed diagnosis and surgical indication. The first-stage imaging methods are ultrasonography and Tc99m sestamibi single photon tomography Tc99mMIBI SPECT or hybrid imaging method, which is combined with both single-photon emission computed tomography and computed tomography (SPECT/CT). The combination of USG and sestamibi scintigraphy increases the localization of the pathological gland. In the secondary stage, Four-Dimensional computer tomography (4D-CT) or dynamic 4-dimensional Magnetic Resonance Imaging (4D-MRI) can be applied. It is focused on as a secondary stage imaging method, especially when the lesion cannot be detected by conventional methods. Positron Emission Tomography (PET) and PET/CT examinations with 11C-choline or 18F-fluorocholine are promising imaging modalities. Invasive examinations can rarely be performed in patients in whom suspicious, incompatible or pathological lesion cannot be detected in noninvasive imaging methods. Bilateral jugular vein sampling, selective venous sampling, parathyroid arteriography, imaging-guided fine-needle aspiration biopsy, and parathormone washout are invasive methods.

Comparison of biochemical markers and technetium 99m methoxyisobutylisonitrile imaging in primary and secondary hyperparathyroidism

OBJECTIVE

To investigate the differences in biochemical marker levels and the extent of lesion visualization on technetium 99m methoxyisobutylisonitrile (^99mTc-MIBI) imaging between primary hyperparathyroidism (PHPT) and secondary hyperparathyroidism (SHPT).

METHODS

Nineteen patients with PHPT and 14 patients with SHPT were enrolled in the study, all of whom underwent routine ^99mTc-MIBI dual-phase planar imaging, single-photon emission computed tomography combined with computed tomography (SPECT/CT fusion) imaging, and serum biochemical and hormonal investigations prior to surgery. The target-to-non-target (T/NT) ratios were calculated based on images from the early and delayed phases of ^99mTc-MIBI planar imaging and also based on SPECT/CT fusion imaging. The volume of the parathyroid glands was measured following their excision.

RESULTS

A total of 62 parathyroid glands were removed: 14 parathyroid adenomas and five parathyroid carcinomas in PHPT patients; and 18 parathyroid adenomas, 17 parathyroid hyperplasia lesions, and eight instances of nodular hyperplasia with adenoma in SHPT patients. The median volume of the lesions in PHPT and SHPT was 1.69 cm³ and 0.52 cm³ respectively, and the difference between them was statistically significant (P = 0.001). The median T/NT ratios calculated at the early phase of ^99mTc-MIBI planar imaging, the delayed phase of ^99mTc-MIBI planar imaging, and the subsequent SPECT/CT fusion imaging were 1.51, 1.34, and 2.75, respectively, in PHPT, and 1.46, 1.30, and 1.38, in SHPT, respectively. The T/NT ratio difference between PHPT and SHPT on the SPECT/CT fusion imaging was statistically significant (P = 0.002). The histopathology subtypes of the lesions were associated with significant differences in two areas: the T/NT ratios on the SPECT/CT fusion imaging and the volume of the lesions (P=0.002, P<0.001).

CONCLUSION

The proportion of positive findings on ^99mTc-MIBI dual-phase planar imaging and the T/NT ratios of ^99mTc-MIBI SPECT/CT fusion imaging were higher in PHPT than in SHPT. The volume of parathyroid lesions in SHPT was smaller than in PHPT.

Disability Weights and Years Lived with Disability of Depression with and Without Suicidality

Background

Globally, depression is a silent epidemic, and more than 350 million people suffer from depression. For a long time, the belief prevailed that children and young people cannot suffer from depressive disorders, and depression is slowly becoming one of the leading health problems among the young population.

Objective

This research aims to determine the mental health disorders burden attributed to depression, anxiousness, and fear with and without suicidal ideation among youth in Bosnia and Herzegovina.

Methods

A prospective cross-sectional study was performed as screening of depression by Hamilton standardized screening instrument from May 3, 2018, to April 4, 2019, among young people, students in secondary schools, and the Faculty of Pharmacy and Medical Faculty of the University of Tuzla in the most populous Tuzla Canton in the Federation of Bosnia and Herzegovina. In achieving the research goals, we expressed the burden attributed to depression with and without suicidality, anxiousness, and fear as Disability Weight (DW) and Years Lived with Disability (YLD). For the population level, YLD was calculated by multiplying DW by the prevalence rate of depression, anxiousness, and fear per thousand of the population (YLD= DW x prevalence/1000), and DW was adjusted for suicidality.

Results

The participants' ages ranged from 16 to 24 years, with a mean of 20,6 ± 1,9 years. The Body mass index (BMI) of 21,9 ± 2,7 is the recommended reference value of 18.5-24.9 kg/m2. The depression score of all participants ranged from 0 to 32 with a mean of 7.4± 6.3, which for our population of respondents at the sample level implies entry into the zone of presence of depressive symptoms. Descriptive statistics and differences per gender in sociodemographic variables (age, education state, and secure monthly existence); and modified factors attributed to satisfaction needs (life satisfaction, hope for the future, support from person of influence). Most participants belong to the age group 19-21 years, 71,44% (n=180), and the same 14,28% (n=36) other age groups (16-18 and 22-24 years), and sixty-two percent of participants are university students, and twenty percent are university failures.

Conclusion

Based on our findings, the very high burden of depression in Bosnia and Herzegovina was found greatly not recognized and unsolved problem among the young population aged 16-24 years. Recognizing and screening depression in young people is the first step to prevention.

Localization and surgical approach to mediastinal parathyroid glands

BACKGROUND

Hyperactive parathyroid glands (PTGs) are in the mediastinum 4.3% of the time. Historically, localization and resection of these glands can be challenging.

METHODS

We searched all operative notes involving a thoracic surgeon and a preoperative diagnosis of hyperparathyroidism from 2001 to 2019.

RESULTS

Eighty-five cases were reviewed, of which 63 were included. Only 14 patients (22%) had de novo hyperparathyroid operations. Seventeen patients (27%) had single-photon emission computed tomography with computed tomography fusion (SPECT-CT) as the only preoperative localization test (excluding chest radiography and ultrasound), and all were resected successfully. The initial surgical approach was transcervical for 16 (27%) patients, however only 7 remained transcervical. 4 (6%) patients had an exploration in which the target lesion was resected but it was not parathyroid tissue.

CONCLUSION

Most patients presenting with mediastinal PTG have had prior HPT surgery. The trend toward more focused HPT surgery may mean more de novo mediastinal PTG resections. An unambiguous functional and anatomic localization test, such as a spect-ct scan, is the best predictor of a successful resection. Ambiguous or discordant scans should be approached cautiously, and additional confirmatory tests are recommended. For suspected PTG located in the thymus, the thoracic surgeon should choose the most familiar approach to achieve complete thymectomy.

Parathyroid Cell Differentiation from Progenitor Cells and Stem Cells: Development, Molecular Mechanism, Function, and Tissue Engineering

Parathyroid glands are endocrine organs which are located posterior to thyroid glands and control secretion of parathyroid hormone (PTH) in order to regulate blood calcium level. PTH maintains calcium homeostasis by acting on the bone, kidney, and small intestine. PTH deficiency leads to chronic hypocalcemia, organ calcinosis, kidney and heart failure, painful muscle spasms, neuromuscular problems, and memory problems. Since parathyroid cells have inadequate proliferation potential in culture conditions, their utilization as a cellular therapy option is very limited. Although studies conducted so far include parathyroid cell differentiation from various cell types, problems related to successful cellular differentiation and transplantation still remain. Recently, parathyroid tissue engineering has attracted attention as a potential treatment for the parathyroid-related diseases caused by hypoparathyroidism. Although major progression is made in the construction of tissue engineering protocols using parathyroid cells and biomaterials, PTH secretion to mimic its spontaneous harmony in the body is a challenge. This chapter comprehensively defines the derivation of parathyroid cells from various cell sources including pluripotent stem cells, molecular mechanisms, and tissue engineering applications.

Accuracy of Parathyroid Adenoma Localization by Preoperative Ultrasound and Sestamibi in 1089 Patients with Primary Hyperparathyroidism

BACKGROUND

Primary hyperparathyroidism (pHPT) is well treatable surgically. Sonography (US) and sestamibi scintigraphy (MIBI) are used routinely, but it is unclear how valuable they are in determining Parathyroid glands' different locations. This study aimed to evaluate the prognostic value of US and MIBI in relation to the different localization of parathyroid adenomas in one of the largest study populations analyzed to date.

METHODS

1089 patients with pHPT who had treatment in one tertiary referral center between 2007 and 2016 were analyzed. Preoperative US and MIBI reports were compared with the parathyroid adenoma's intraoperative localization. All parathyroid glands were confirmed by histological diagnosis.

RESULTS

No gland was detectable in 22.5% and 27.7% of all patients, by US or by MIBI, respectively. In relation to the different adenoma locations, the sensitivity of US ranged from 21.3% (upper right) to 68.9% (lower left) and of MIBI ranged from 23.5% (upper right) to 72% (lower left). The specificity for US ranged from 85% (lower right) to 99.2% (upper right) and for MIBI ranged from 86.1% (lower right) to 99.1% (upper right. Positive predictive values for all gland sites were 54% and 59% for MIBI and US, respectively. The value increased for side-only prediction to 73% and 78%, respectively. Neither the parathyroid hormone level nor the calcium value level influenced the sensitivity or specificity of the two test methods.

CONCLUSIONS

The validity of preoperative US and MIBI depends crucially on the specific localization of adenomas. This should be considered when planning the extent of parathyroid surgery.

An essential practice summary of the new EANM guidelines for parathyroid imaging

Parathyroid imaging is essential for the detection and localization of hyperfunctioning parathyroid tissue in patients with primary hyperparathyroidism (pHPT). Surgical treatment of pHPT mainly consists of minimally invasive parathyroidectomy (MIP), as a single adenoma represents the most common cause of this endocrine disorder. Successful surgery requires an experienced surgeon and relies on the correct preoperative detection and localization of hyperfunctioning parathyroid glands. Failure to preoperatively identify the culprit parathyroid gland by imaging may entail a more invasive surgical approach, including bilateral open neck exploration, with higher morbidity compared to minimally invasive parathyroidectomy. Parathyroid imaging may be also useful before surgery in case of secondary hyperparathyroidism (sHPT) or hereditary disorders (MEN 1, 2, 4) as it enables correct localization of typically located parathyroid glands, detection of ectopic as well as supernumerary glands. It is now accepted by most surgeons experienced in parathyroid surgery that preoperative imaging plays a key role in their patients' management. Recently, the European Association of Nuclear Medicine (EANM) issued an updated version of its Guidelines on parathyroid imaging. Its aim is to precise the role and the advantages and drawbacks of the various imaging modalities proposed or well established in the preoperative imaging strategy. It also aims to favor high performance in indicating, performing, and interpreting those examinations. The objective of the present article is to offer a summary of those recent EANM Guidelines and their originality among other Guidelines in this domain issued by societies of nuclear medicine physicians or other disciplines.

Contemporary Multimodality Imaging of Primary Hyperparathyroidism

Primary hyperparathyroidism (PHPT) is a disorder characterized by hypercalcemia and an elevated or inappropriately normal parathyroid hormone level. Classic features include bone pain, fractures, renal impairment, nephrolithiasis, and mental disturbance. However, most cases of PHPT are now asymptomatic at diagnosis or associated with nonspecific neurocognitive changes. The most frequent cause of PHPT is a solitary adenoma that secretes parathyroid hormone without the normal suppressive effect of serum calcium. A smaller number of cases can be attributed to multigland disease. Parathyroidectomy is curative and is considered for nearly all affected patients. Although PHPT is primarily a clinical and biochemical diagnosis, imaging is key to the localization of adenomas, which can lie in conventional locations adjacent to the thyroid gland or less commonly at ectopic sites in the neck and mediastinum. In addition, accurate localization facilitates the use of a minimally invasive or targeted surgical approach. Frequently used localization techniques include US, parathyroid scintigraphy, and four-dimensional CT. Second- and third-line modalities such as MRI, PET/CT, and selective venous sampling with or without parathyroid arteriography can increase confidence before surgery. These localization techniques, along with the associated technical aspects, relative advantages, and drawbacks, are described. Local expertise, patient factors, and surgeon preference are important considerations when determining the type and sequence of investigation. A multimodality approach is ultimately desirable, particularly in challenging scenarios such as multigland disease, localization of ectopic adenomas, and persistent or recurrent PHPT. Online supplemental material is available for this article. ^©RSNA, 2022.

Ultrasound-guided thermal ablation for hyperparathyroidism: current status and prospects

BACKGROUND

Hyperparathyroidism (HPT) is classified into primary HPT (PHPT), secondary HPT (SHPT), tertiary HPT (THPT), and pseudohyperparathyroidism. Parathyroid surgery is generally reserved for patients with symptomatic PHPT and asymptomatic patients who meet the surgical guideline criteria. However, the risk of complications and mortality after parathyroid gland surgery increases with increasing patient age.

AIM

This study aimed to review existing research on laser ablation, radiofrequency ablation, microwave ablation, and high-intensity focused ultrasound in the treatment of HPT and analyze its application prospects.

CONCLUSIONS

Thermal ablation is a good alternative treatment for patients with parathyroid hyperplasia who do not meet the criteria or decline surgery. Being a type of minimally invasive treatment, ultrasound-guided thermal ablation has the advantages of easy operation, rapid recovery, and reusability and is used widely.

Transoral robotic surgical excision of hypopharyngeal ectopic parathyroid adenoma causing primary hyperparathyroidism

Ectopic parathyroid adenomas are a rare congenital anomaly despite the complex migration parathyroid glands undergo during development. Rarer still, these can be found in the hypopharynx, become adenomas and be the cause of primary hyperparathyroidism. We present a case of a woman in her 50s who underwent transoral robotic surgery (TORS) to remove her hypopharyngeal ectopic parathyroid adenoma and cure her primary hyperparathyroidism without complication. This is a radical change in practice compared with traditional open, transverse cervical approaches. We demonstrate the efficacy of using TORS for this unusual case, highlighting its versatility and the need to continue to search for opportunities to best use this advancing technology, especially when it can improve patient outcomes.

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.

Primary hyperparathyroidism-related giant parathyroid adenoma (Review)

Primary hyperparathyroidism (PHPT), an endocrine condition caused by a parathyroid adenoma (PTA) in 80-85% of the cases, has shifted in the modern era to a mildly symptomatic phenotype due to the prompt recognition of hypercalcemia and to a minimally invasive surgical approach which has a curative potential. Clinical complications of PHTH are either related to high calcium or parathyroid hormone [also parathormone (PTH)] or both, while the originating tumor typically is small, without local mass effects. A distinct entity is represented by giant PTA (GPTA) which is considered at a weight of more than 3 (3.5) grams. The present article is a review of the literature involving practical points of non-syndromic PHPT-related GPTA. Most authors agree that pre-operatory calcium and PTH are higher in GPTA vs. non-GPTA. However, the clinical presentation of PHPT may be less severe, probably due to local mass effects that bring the patient to an early medical evaluation. Age distribution, sex ratio, rate of successful pre-operatory location do not differ from non-giant PTA. Hypovitaminosis D is more frequent in PTA of higher dimensions. Post-operative hypocalcemia, but not recurrent/persistent PHPT, is expected, even hungry bone disease. A higher rate of atypia is described although the tumor is mostly benign. Unusual presentations such as cystic transformation, initial diagnosis during pregnancy or auto-infarction have been reported. The ectopic localization of PTA presented in almost 15% of all cases may also be found in GPTA. What are the exact cutoffs for defining GPTA is still an open issue.

Surgical results and the location of pathological glands in the treatment of primary sporadic hyperparathyroidism with negative preoperative 99mTc-sestamibi scintigraphy

INTRODUCTION

The primary hyperparathyroidism is a frequent disease whom the surgery is the only curative treatment. The preoperative location imaging techniques could help in the surgical management. Our objective was to analyze surgical results regarding the cure rate, etiology and location of the glands responsible for the primary hyperparathyroidism in patients with negative preoperative ^99mTc-sestamibi scintigraphy.

METHODS

Observational study in patients with the diagnosis of primary sporadic hyperparathyroidism with negative ^99mTc-sestamibi scintigraphy, operated consecutively in an endocrine surgery unit for 18 years. The cure rate, the intraoperatory PTH, the etiology and the pathological glands location were analyzed.

RESULTS

In the study were included 120 patients. After surgery 95% of patients (n = 114) presented cure criteria of hyperparathyroidism. 14.1% presented a multigland disease. 69% of the adenomas presented a typical perithyroid location, founding a percentage of 23.9% of ectopic adenomas in cervical location and a 7.1% in mediastinum.

CONCLUSIONS

The absence of uptake in the ^99mTc-sestamibi scintigraphy should not condition the surgical indication. The success with experienced surgeons is similar to patients with positive results. The surgical indication must be established by clinical and biochemistry criteria.

Are Non-Coding RNAs Useful Biomarkers in Parathyroid Tumorigenesis?

Tumors of the parathyroid glands are common endocrine diseases almost always characterized by parathyroid hormone hypersecretion that determines the clinical manifestations of primary hyperparathyroidism, such as fatigue, kidney problems, weakness, brittle bones, and other symptoms. Most parathyroid neoplasia are benign adenomas, although rare malignant forms have been described. They are heterogeneous in terms of clinical presentation and the associated signs and symptoms overlap with those of disease and aging. Furthermore, most patients with hypercalcemia are discovered during routine blood tests for other reasons. Surgical removal is considered the main therapeutic option to cure these endocrine tumors and, therefore, innovative therapeutic approaches are actively required. Recently, a growing number of studies have suggested that alterations to the epigenetic mechanisms could play a pivotal role in parathyroid tumorigenesis. Most of the attention has been focused on non-coding RNAs (ncRNAs) (i.e., miRNAs, lncRNAs, and circRNAs) whose expression profile has been found to be deregulated in parathyroid tumors. The aim of the present paper is to give an insight into the ncRNAs involved in parathyroid tumorigenesis, which could be used in the future either as innovative diagnostic biomarkers or as therapeutic targets for the treatment of this endocrine neoplasia.

Methods of identification of parathyroid glands in thyroid surgery: A literature review

Intra-operative identification and preservation of parathyroid glands is an important but challenging aspect of thyroid surgery. Failure to do so may lead to transient or permanent hypocalcaemia, where the latter represents a serious complication causing life-long morbidity. It would be beneficial, therefore, if a simple and reliable modality can be developed to assist in the identification of parathyroid glands intra-operatively. The aim of this literature review is to provide an overview of intra-operative modalities used to identify parathyroid glands with a particular focus on near-infrared autofluorescence (NIRAF). Twenty-seven studies were considered relevant in this literature review. Several modalities have been used to aid parathyroid gland identification, including Raman spectroscopy, indocyanine green angiography, and NIRAF. NIRAF technology allows parathyroid glands to spontaneously give off light (autofluorescence) when exposed to near-infrared light at a wavelength of 785 nm, creating a contrast between tissues to allow intra-operative differentiation. Studies utilising NIRAF technology were able to identify 76.3%-100% of parathyroid glands intra-operatively. Furthermore, two randomised controlled trials comparing NIRAF and white light showed that the use of NIRAF was able to significantly increase the mean number of parathyroid glands detected and reduce the incidence of post-operative hypocalcaemia. NIRAF is an emerging tool that has been shown to increase the number of intra-operative parathyroid gland identification and reduce the rate of post-operative hypocalcaemia in a safe and reproducible manner. Future trials are needed to evaluate the real-life impact of NIRAF technology in outcomes of patients following thyroid surgery.

The EANM practice guidelines for parathyroid imaging

INTRODUCTION

Nuclear medicine parathyroid imaging is important in the identification of hyperfunctioning parathyroid glands in primary hyperparathyroidism (pHPT), but it may be also valuable before surgical treatment in secondary hyperparathyroidism (sHPT). Parathyroid radionuclide imaging with scintigraphy or positron emission tomography (PET) is a highly sensitive procedure for the assessment of the presence and number of hyperfunctioning parathyroid glands, located either at typical sites or ectopically. The treatment of pHPT is mostly directed toward minimally invasive parathyroidectomy, especially in cases with a single adenoma. In experienced hands, successful surgery depends mainly on the exact preoperative localization of one or more hyperfunctioning parathyroid adenomas. Failure to preoperatively identify the hyperfunctioning parathyroid gland challenges minimally invasive parathyroidectomy and might require bilateral open neck exploration.

METHODS

Over a decade has now passed since the European Association of Nuclear Medicine (EANM) issued the first edition of the guideline on parathyroid imaging, and a number of new insights and techniques have been developed since. The aim of the present document is to provide state-of-the-art guidelines for nuclear medicine physicians performing parathyroid scintigraphy, single-photon emission computed tomography/computed tomography (SPECT/CT), positron emission tomography/computed tomography (PET/CT), and positron emission tomography/magnetic resonance imaging (PET/MRI) in patients with pHPT, as well as in those with sHPT.

CONCLUSION

These guidelines are written and authorized by the EANM to promote optimal parathyroid imaging. They will assist nuclear medicine physicians in the detection and correct localization of hyperfunctioning parathyroid lesions.