Pathology of the parathyroid glands in hyperparathyroidism

Normal Parathyroid Glands Are Most Often Seen on Neck Ultrasound

RATIONALE AND OBJECTIVES

The dogma is that normal parathyroid glands (PTGs) are not visible on ultrasound (US). Recently, several studies have shown that PTGs present these US features: ovoid structure, homogeneous and hyperechoic. The primary objective was to assess the detection rate, standard size and locations of normal PTGs in a population of patients consulting for thyroid US exam. The secondary objective was to determine if the presence of a goiter or a thyroiditis could modify the visualization of normal PTGs.

METHOD

Single-center prospective study on 192 patients based on the typical US appearance previously described to identify one or more PTGs.

RESULTS

One or more PTGs were visualized in 75% of patients (144/192). They were visualized preferentially at the lower pole of the thyroid gland and in the infra-thyroid region (66%). The mean (± SD) size of normal PTGs was 5.68 mm (± 1,42 mm)×4.05 mm (± 1,03 mm)×2,68 mm (± 0,61 mm) and mean volume was 33.3 mm3 (± 17.75 mm3). The presence of a goiter made the search for PTGs more difficult whereas the presence of thyroiditis facilitated it.

CONCLUSION

The US detection rate of PTGs is high (75%). The identification of PTGs could be particularly useful in the preoperative assessment before total thyroidectomy or parathyroid surgery. It could reduce the risk of postoperative hypoparathyroidism and improve the accuracy of postoperative US surveillance of thyroid cancer. Better knowledge of the usual anatomical location of normal PTGs could also enable better detection of abnormal glands.

Syndromic MEN1 parathyroid adenomas consist of both subclonal nodules and clonally independent tumors

Primary hyperparathyroidism with parathyroid tumors is a typical manifestation of Multiple Endocrine Neoplasia Type 1 (MEN1) and is historically termed "primary hyperplasia". Whether these tumors represent a multi-glandular clonal disease or hyperplasia has not been robustly proven so far. Loss of Menin protein expression is associated with inactivation of both alleles and a good surrogate for a MEN1 gene mutation. The cyclin-dependent kinase inhibitor 1B (CDKN1B) gene is mutated in MEN4 and encodes for protein p27 whose expression is poorly studied in the syndromic MEN1 setting.Here, we analyzed histomorphology and protein expression of Menin and p27 in parathyroid adenomas of 25 patients of two independent, well-characterized MEN1 cohorts. The pattern of loss of heterozygosity (LOH) was assessed by fluorescence in situ hybridization (FISH) in one MEN1-associated parathyroid adenoma. Further, next-generation sequencing (NGS) was performed on eleven nodules of four MEN1 patients.Morphologically, the majority of MEN1 adenomas consisted of multiple distinct nodules, in which Menin expression was mostly lost and p27 protein expression reduced. FISH analysis revealed that most nodules exhibited MEN1 loss, with or without the loss of centromere 11. NGS demonstrated both subclonal evolution and the existence of clonally unrelated tumors.Syndromic MEN1 parathyroid adenomas therefore consist of multiple clones with subclones, which supports the current concept of the novel WHO classification of parathyroid tumors (2022). p27 expression was lost in a large fraction of MEN1 parathyroids and must therefore be used with caution in suggesting MEN4.

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.

FCH-PET/CT in Primary Hyperparathyroidism With Discordant/Negative MIBI Scintigraphy and Ultrasonography

CONTEXT

The contribution of [18F]F-fluorocholine (FCH)-positron emission tomography (PET)/computed tomography (CT) in normocalcemic primary hyperparathyroidism (nPHPT) remains unknown.

OBJECTIVE

To evaluate the sensitivity and specificity of FCH-PET/CT in a cohort of osteoporotic patients with nPHPT and discordant or negative [99mTc]Tc-sestamibi scintigraphy and ultrasonography who all underwent parathyroidectomy (PTX).

DESIGN

Longitudinal retrospective cohort study in patients referred for osteoporosis with mild biological primary hyperparathyroidism.

SETTING

Tertiary referral center with expertise in bone metabolism and surgical management of hyperparathyroidism.

PATIENTS

Among 109 patients with PHPT analyzed, 3 groups were individualized according to total serum calcium (tCa) and ionized calcium (iCa): 32 patients with hypercalcemia (HtCa group), 39 patients with normal tCa and elevated iCa (NtCa group), and 38 patients with both normal tCa and iCa (NiCa). All patients had biochemical follow-up confirming or not the success of PTX.

MAIN OUTCOME MEASURES

To evaluate the performance of FCH-PET/CT in terms of sensitivity and specificity, and to compare with first-line imaging procedures in the setting of nPHPT.

RESULTS

The sensitivity of FCH-PET/CT was 67% in the hypercalcemic group, 48% in the NtCa group (P = .05 vs HtCa), and 33% in the NiCa group (P = .004 vs HtCa). Specificity ranged from 97% to 99%. FCH-PET/CT was positive in 64.3% of patients with negative conventional imaging, with biochemical resolution after PTX in 77.8% of patients. Triple negative imaging was observed in 20 patients, with PHPT resolution in 85% of these patients.

CONCLUSION

This study highlights the contribution of FCH-PET/CT in a well-phenotyped cohort of normocalcemic patients with discordant or negative findings in [99mTc]Tc-sestamibi scintigraphy and ultrasonography. However, negative imaging in nPHPT does not rule out the possibility of surgical cure by an experienced surgeon.

Genomic Profiling Reveals the Variant Landscape of Sporadic Parathyroid Adenomas in Chinese Population

OBJECTIVE

To define somatic variants of parathyroid adenoma (PA) and to provide novel insights into the underlying molecular mechanism of sporadic PA.

METHODS

Basic clinical characteristics and biochemical indices of 73 patients with PA were collected. Whole-exome sequencing was performed on matched tumor-constitutional DNA pairs to detect somatic alterations. Functional annotation was carried out by ingenuity pathway analysis afterward. The protein expression of the variant gene was confirmed by immunohistochemistry, and the relationship between genotype and phenotype was analyzed.

RESULTS

Somatic variants were identified in 1549 genes, with an average of 69 variants per tumor (range, 13-2109; total, 9083). Several novel recurrent somatic variants were detected, such as KMT2D (15/73), MUC4 (14/73), POTEH (13/73), CD22 (12/73), HSPA2 (12/73), HCFC1 (11/73), MAGEA1 (11/73), and SLC4A3 (11/73), besides the previously reported PA-related genes, including MEN1 (11/73), CASR (6/73), MTOR (4/73), ASXL3 (3/73), FAT1 (3/73), ZFX (5/73), EZH1 (2/73), POT1 (2/73), and EZH2 (1/73). Among them, KMT2D might be the candidate driver gene of PA. Crucially, 5 patients carried somatic mutations in CDC73, showed an aggressive phenotype similar to that of parathyroid carcinoma (PC), and had a decreased expression of parafibromin. Pathway analysis of recurrent potential PA-associated driver variant genes revealed functional enrichments in the signaling pathway of Notch.

CONCLUSION

Our study expanded the pathogenic variant spectrum of PA and indicated that KMT2D might be a novel candidate driver gene and be considered as a diagnostic biomarker for PA. Meanwhile, CDC73 mutations might be an early developmental event from PA to PC. The results provided insights into elucidating the pathogenesis of parathyroid tumorigenesis and a certain basis for clinical diagnosis and treatment.

Advances and Updates in Parathyroid Pathology

Hyperparathyroidism is a common endocrine disorder characterized by elevated levels of parathyroid hormone and hypercalcemia and is divided into 3 types: primary, secondary, and tertiary. Distinction between these types is accomplished by correlation of clinical, radiologic, and laboratory findings with pathologic features. Primary hyperparathyroidism occurs sporadically in 85% of cases with the remaining cases associated with multiple familial syndromes. The pathologic manifestations of primary hyperparathyroidism include parathyroid adenoma, parathyroid hyperplasia, and parathyroid carcinoma. Recent advances in the understanding of the pathogenesis of parathyroid disease has helped to refine the diagnosis and classification of parathyroid lesions. The identification of multiple clonal proliferations in traditional multiglandular parathyroid hyperplasia has led to the adoption by the World Health Organization (WHO) of the alternate term of primary hyperparathyroidism-related multiglandular parathyroid disease. Additional nomenclature changes include the adoption of the term atypical parathyroid tumor in lieu of atypical parathyroid adenoma to reflect the uncertain malignant potential of these neoplasms. Clinical and morphologic features characteristic of familial disease have been described that can help the practicing pathologist identify underlying familial disease and provide appropriate management. Use of ancillary immunohistochemistry and molecular studies can be helpful in classifying parathyroid neoplasms. Parafibromin has proven useful as a diagnostic and prognostic marker in atypical parathyroid tumors and parathyroid carcinomas. This review provides an update on the diagnosis and classification of parathyroid lesions considering the recent advances in the understanding of the molecular and clinical features of parathyroid disease and highlights the use of ancillary studies (immunohistochemical, and molecular) to refine the diagnosis of parathyroid lesions.

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.

Correlation between preoperative calcium and parathormone levels with parathyroid gland volume

Objective. Hyperparathyroidism is a prevalent disease with parathyroid adenomas being the most common cause. Surgical excision remains the standard treatment for parathyroid adenoma. Successful preoperative localization of the parathyroid adenoma could facilitate the decision regarding the extent of surgical exploration. The aim of the current study was to assess the correlation between the preoperative values of parathyroid hormone and ionized calcium with the adenoma weight and volume in patient with primary hyperparathyroidism caused by single-gland adenoma. Patients and Methods. We did this retrospective review for all patients who were diagnosed with primary hyperparathyroidism due to a solitary parathyroid adenoma in our general surgery department over 4 years. SPSS software was used to get the correlation coefficient between the peak preoperative levels of calcium and parathyroid hormone with the parathyroid adenoma weight and volume. Results. Ninety-nine patients were included into the study. The average age at surgery was 62.65±12.00 years. The correlation coefficient between the adenoma volume and weight with the preoperative ionized calcium level was weakly positive (r=0.329, p<0.01) and (r=0.281, p=0.019), respectively, while the correlation with the preoperative parathyroid hormone level was stronger (r=0.708, p<0.01) and (r=0.650, p<0.01), respectively. Conclusions. The strong positive relationship between the preoperative parathyroid hormone and calcium levels with the parathyroid adenoma size and weight can help the surgeon to predict the volume of the involved gland and avoid an unnecessary dissection.

Giant Ectopic Parathyroid Adenoma Arising in the Posterior Mediastinum. Report of Case and a Review

We present a case of a greatly enlarged giant ectopic parathyroid adenoma that weighed 43 grams, which was located in the posterior mediastinum of a 74-year-old man. The patient presented with generalized weakness and decreased level of consciousness. He was found to have elevated level of serum calcium (19.9 mg/dl), and a subsequent assay of parathyroid hormone (PTH) was greatly elevated (2234 pg/ml). We report the course of management and outcome of the patient and present a review of the literature on giant ectopic parathyroid adenomas in the posterior mediastinum.

Risk factors influencing cure of ultrasound-guided microwave ablation for primary hyperparathyroidism

OBJECTIVE

To evaluate the potential risk factors influencing cure rate of ultrasound-guided microwave ablation (MWA) for primary hyperparathyroidism (PHPT).

MATERIALS AND METHODS

Seventy five patients (25 males and 50 females; mean age, 56.80 ± 12.34; age range, 26-85) with PHPT undergoing MWA under ultrasound guidance were enrolled between May 2017 and December 2020. The cure rate and complications were evaluated after treatment. The potential factors influencing cure rate of ultrasound-guided MWA for PHPT were analyzed by univariate and multivariate binary logistic regression.

RESULTS

Fifty six of 75 patients had normal PTH and serum calcium levels after at least 6 months after one session MWA, and the cure rate was 74.7% (56/75). 6 uncured patients received the second session MWA during follow-up, and the cure rate achieved 81.3% (61/75) after the second session MWA. Voice changes occurred in 4 patients (5.33%) and recovered within 3 months after ablation without special treatment. Nodule volume was the independent risk factor associated with cure in PHPT patients undergoing MWA, whether after one session (p = 0.0224; odds ratio, 0.67) or the second session MWA (p = 0.0408; odds ratio, 0.74). The cutoff value for nodule volume in predicting the cure was 0.96 cm³ (one session: sensitivity, 76.8%; specificity, 73.7%; the second session: sensitivity, 72.1%; specificity, 71.4%).

CONCLUSION

In conclusion, parathyroid nodule volume was the independent risk factor associated with cure in PHPT patients undergoing MWA.

Comparative analysis of clinicopathologic features between adenoma and hyperplasia in surgically treated patients for hyperparathyroidism: A retrospective study

BACKGROUND

Hyperparathyroidism (HPT) is a common endocrine disorder resulting from overproduction of parathyroid hormone (PTH). Usually HPT is caused by parathyroid adenoma (PA) or parathyroid hyperplasia (PH). Our aim is to assess clinicopathologic features associated with PA and PH in patients with HPT.

METHODS

We retrospectively collected 29 cases of HPT recorded at the Department of Pathology of Hassan II University Hospital of Fes, Morocco, from 2013 to 2016.

RESULTS

The mean age was 52.14 ± 15.7 years (range of 22-76 years), 13 patients (44.8%) had primary HPT, 16 (55.2%) had secondary HPT. The largest size of the resected parathyroid specimens ranged from 1 to 3.6 cm (mean of 2.26 ± 0.66 cm). Seventeen patients (58.6%) had PA, the remaining cases were diagnosed as PH. There were no significant statistical differences between PA and PH in age, sex, clinical presentation, preoperative serum PTH, or in parathyroid gland size (P > 0.05). However compared to PH, PA is more often a single-gland disease, found in primary HPT with higher preoperative calcium level (P ˂ 0.05).

CONCLUSIONS

In patients surgically treated for HPT, PA is associated with some distinctive clinicopathologic features. These findings could be helpful to pathologists and clinicians for appropriate clinicopathologic management.

Major Clues and Pitfalls in the Differential Diagnosis of Parathyroid and Thyroid Lesions Using Fine Needle Aspiration Cytology

Background: It is difficult to distinguish parathyroid lesions (PLs) from thyroid lesions using fine needle aspiration cytology (FNAC) because of their proximity and their similar cytomorphological features. Methods: FNAC smears of 46 patients with pathologically proven PLs that were histologically diagnosed as parathyroid adenoma (PA, n = 35), parathyroid hyperplasia (PH, n = 3), atypical parathyroid adenoma (APA, n = 1), and parathyroid carcinoma (PC, n = 7) were retrospectively reviewed and analyzed. Results: Our initial cytological diagnoses indicated correct diagnoses in 31 of 46 PL patients (67%). The 15 erroneous diagnoses were 5 patients with non-specific benign disease (11%), 4 with nodular hyperplasia of the thyroid (9%), 5 with atypical cells (11%), and 1 with a metastatic papillary thyroid carcinoma (2%). Follicular pattern, papillary structures, colloid-like material, and macrophages, which often suggest thyroid lesions, were also present in some PLs. We found that branching capillaries along the papillary structures, stippled nuclear chromatin, and frequent occurrence of naked nuclei were useful for determining a parathyroid origin. Conclusions: It is important to be aware that PLs are frequently mistaken for thyroid lesions based on FNAC. The specific and unique characteristics of PLs identified here may be helpful in diagnosis.

Histologic hypercellularity in a biopsied normal parathyroid gland does not correlate with hyperfunction in primary hyperparathyroidism

BACKGROUND

About 15% of patients with primary hyperparathyroidism have multiglandular disease, thus during resection of an apparent single adenoma, a visibly normal parathyroid may be identified and biopsied. Using long-term biochemical follow-up, we examined whether normal parathyroid hypercellularity correlates with multiglandular disease or primary hyperparathyroidism recurrence.

METHODS

We reviewed all patients who from 2001 to 2015 had an initial operation for sporadic primary hyperparathyroidism with removal of 1 gland, routine normal parathyroid biopsy, intraoperative parathyroid hormone monitoring, and follow-up of ≥3 years. Recurrence was defined by hypercalcemia after documented cure at 6 months, and hypercellularity by standard histologic criteria.

RESULTS

Of 134 patients with mean follow-up of 9.4 years (range, 3.1-15.9), 132 (98.5%) exhibited cure at 6 months. Two had initial failure, and 8 of 132 (6.1%) developed recurrent hyperparathyroidism (mean 5.8 y, range 4-10.6). The normal parathyroid was hypercellular in 14 of 132 (10.6%) of the cured patients, and this rate did not differ for those with long-term cure (12/124, 9.7%) versus recurrence (2/8, 25%, P = .2). The positive predictive value of normal parathyroid hypercellularity for recurrence was low (14.3%), and the negative predictive value of normal parathyroid normocellularity was high (94.9%).

CONCLUSION

During the initial operation for primary hyperparathyroidism, 10% of normal parathyroids are hypercellular, but this does not signify missed multiglandular disease. In contrast, normal parathyroid normocellularity has high predictive value for durable cure (95%), slightly better than visual identification of a second normal parathyroid (94%).

Hypercalcemia in the Presence of an Ectopic Mediastinal Mass

A 72-year-old gentleman who presented to the outpatient clinic for a preventive health appointment with symptoms of depression and fatigue was found to have persistent hypercalcemia on routine laboratory monitoring. Initial laboratory testing was consistent with primary hyperparathyroidism with elevation in parathyroid hormone and low vitamin D levels. Further imaging demonstrated an ectopic mediastinal parathyroid adenoma. The ectopic lesion was treated surgically and lead to normalization of calcium levels and objective improvement in depressive symptoms. Primary hyperparathyroidism, which can be secondary to an adenoma, multigland hyperplasia, or neoplasm, can lead to the development of bone pain, fractures, and nephrolithiasis among other symptoms. The evaluation of hypercalcemia and the identification of primary hyperparathyroidism are important for the primary care physician to recognize so as to reduce disease morbidity as well as identify patients in need of further specialty care.

New Concepts About Familial Isolated Hyperparathyroidism

CONTEXT

Familial isolated hyperparathyroidism (FIHP) is defined as familial primary hyperparathyroidism (FH) without a characteristic extra-parathyroidal feature of a more complex hyperparathyroid syndrome. During 80 years, new concepts of FIHP have been developed within this definition. FIHP has been difficult to study due to small kindreds and mildly symptomatic cases.

EVIDENCE ACQUISITION

Searches were through PubMed for FIHP, other FH syndromes, and the gene(s) mutated in each.

EVIDENCE SYNTHESIS

Within its definition, the current concept of FIHP has clinical and mutational components. It can include incomplete expressions of MEN1 FHH, or HPT-JT or their mutations. Newest concepts of FIHP focus upon kindreds without mutation of either the MEN1, CASR, or CDC73 gene; 17% have germline activating mutation of the gene for the GCM2 transcription factor. Other genes for FIHP will probably be identified shortly. The FIHP kindreds with or without GCM2 mutation contain a median of only 2 cases of PHPT. The small kindred size in both subgroups of FIHP is probably caused low rate of screening among relatives. PHPT in FIHP with GCM2 mutation seems similar to PHPT in MEN1. Persons with FIHP and GCM2 mutation present as adults with mild hypercalcemia and multiple parathyroid tumors.

CONCLUSIONS

The current concept of FIHP led to a focus on small kindreds without mutation of MEN1, CASR, or CDC73. These assisted in the identification of germline activating GCM2 mutations in 17%. There is a need for clinical and mutational characterization in more cases to determine any unique clinical features of FIHP, either with or without mutation of GCM2.

The characteristics of clinical changes in primary hyperparathyroidism in Chinese patients

In Western countries, the presentation of primary hyperparathyroidism (PHPT) changed from a symptomatic to an asymptomatic disease after the 1970s, whereas in China, only one study has evaluated the changing clinical characteristics and biochemical profiles of PHPT patients. The aim of this study was to explore changes in the clinical characteristics of PHPT in Chinese patients. Overall, 140 consecutive patients with PHPT were studied between January 1, 2010 and June 30, 2016. The patients were divided into two groups: 32 consecutive patients from January 1, 2010 to March 31, 2013 were included in group 1, and 108 consecutive patients from April 1, 2013 to June 30, 2016 were included in group 2. The most frequent complaints were ostealgia (46.02%), urolithiasis (41.59%), constipation (25.66%), fatigue (18.58%), polydipsia and polyuria (15.93%) and fracture history (15.04%). The number of cases in group 2 was 3.38-fold greater than that of group 1. The parathyroid hormone (PTH) and fasting blood glucose (FPG) levels were higher in group 1 than those in group 2 (p = 0.039, p < 0.001). In 62.14% of patients with PHPT, the proportion of the first diagnosis due to hypercalcemia found using a multichannel autoanalyzer in group 1 was lower than that found in group 2 (p = 0.039), and the proportion of the first diagnosis due to parathyroid lesions captured using routine neck ultrasonography in group 1 was higher than in group 2 (p = 0.003). The proportion of parathyroid carcinoma cases was higher in group 1 than group 2 (p = 0.036). Cases of PHPT increased with time, but the proportion of parathyroid carcinoma cases was lower in group 1 than that in group 2. Over time, the first diagnosis switched from parathyroid lesions captured by routine neck ultrasound to hypercalcemia found by a multichannel autoanalyser. At our centre, PHPT in Chinese patients still demonstrates classic characteristics.

Microwave ablation vs. parathyroidectomy for secondary hyperparathyroidism in maintenance hemodialysis patients

INTRODUCTION

Secondary hyperparathyroidism (SHPT) is a serious and common problem in patients undergoing maintenance hemodialysis. Minimally invasive microwave ablation (MWA) has been used to treat SHPT and shows some advantages. However, its efficacy is still undefined. The primary purpose of this study was to determine the efficacy and safety of MWA compared to total parathyroidectomy plus forearm autotransplantation.

METHODS

The SHPT patients who were undergoing maintenance hemodialysis (follow-up for 6 to 24 months after treatments) were divided into a MWA group (n = 33) and a parathyroidectomy group (n = 48). The efficacy (serum intact parathyroid hormone [iPTH], calcium, and phosphorus levels) and safety (hoarseness, hypocalcaemia, and persistently low iPTH) were compared between the two groups. Additionally, the study explored potential predictors of response to MWA by a logistic regression analysis.

FINDINGS

There were no significant differences in baseline characteristics between the two groups. The rates of achieving the recommended goal for iPTH were significantly higher in the MWA group than that in the parathyroidectomy group at all follow-up times: 57.58% vs. 12.50% at one-day (P < 0.001), 45.45% vs. 16.67% at 1-week (P = 0.005), 57.58% vs. 16.67% at 2-week (P < 0.001), 57.58% vs. 22.92% at 1-month (P = 0.002), and 69.70% vs. 35.42% at 3-month (P = 0.002), 76.47% vs. 28.57% at 6-month (P = 0.005), 87.50% vs. 47.37% at 12-month (P = 0.008), and 81.82% vs. 52.63% at 24-month (P = 0.015), respectively. However, there were no significant differences for phosphorus or calcium at any of the follow-up times (P > 0.05). The persistently low iPTH was more in the parathyroidectomy group (64.6%) than that in the MWA group (0%) (P < 0.001), but there was no significant difference in hoarseness or hypocalcaemia (P > 0.05). Baseline levels of iPTH (P = 0.021) and patient age (P = 0.011) were determined as predictors by univariate logistic regression analysis.

CONCLUSION

The MWA could be an alternative to parathyroidectomy for SHPT but its eventual superiority has to be demonstrated by a proper study.

Diagnosis, management, histology and genetics of sporadic primary hyperparathyroidism: old knowledge with new tricks

Primary hyperparathyroidism (pHPT) is a common endocrinopathy resulting from inappropriately high PTH secretion. It usually results from the presence of a single gland adenoma, multiple gland hyperplasia or rarely parathyroid carcinoma. All these conditions require different management, and it is important to be able to differentiate the underlined pathology, in order for the clinicians to provide the best therapeutic approach. Elucidation of the genetic background of each of these clinical entities would be of great interest. However, the molecular factors that control parathyroid tumorigenesis are poorly understood. There are data implicating the existence of specific genetic pathways involved in the emergence of parathyroid tumorigenesis. The main focus of the present study is to present the current optimal diagnostic and management protocols for pHPT as well as to review the literature regarding all molecular and genetic pathways that are to be involved in the pathophysiology of sporadic pHPT.

Fine needle cytology pre-surgical differentiation of parathyroid neoplasms: Is it reliable?

BACKGROUND

Fine needle cytology (FNC) of a parathyroid neoplasia (PN) is reliable, but needs to be confirmed by Parathormone (PTH) and Thyroglobulin (TG) immunoassay on needle washing or by immunocytochemistry (ICC) evaluation. The differentiation between parathyroid adenoma (PA), atypical adenoma (PAA) and carcinoma (PC) is difficult on histology or even impossible on FNC. The aim of this study was to evaluate possible cytological criteria to classify FNC-PN further.

METHODS

Twenty-three FNC samples of PN and parathyroid cysts were rather then have been reviewed. The series includes 18 PNs, 4 cysts and 1 Thyr3B (histologically diagnosed as PA). Cytological features were: cellularity, patterns (follicular, solid or papillary), clear, oncocytic, isolated cells, nuclear atypia, cytoplasmic inclusions, nucleoli and mitoses. Data were compared with the histological controls.

RESULTS

Seventeen PNs, 2 cysts and 1 Thyr3B FNC samples were histologically diagnosed as PA (16), PAA (2) and PC (2). Two cysts and 1 PN were not confirmed histologically. Cytological features and incidences were: high cellularity (1 PA, 1 PAA, 2 PCs), follicular (8 PAs, 1 PAA), solid (5 PAs, 1 PC), papillary pattern (1PA, 1 PAA, 1 PC), clear cells (4 PAs, 1 PAA, 2 PCs), oncocytic cells (6 PAs, 1 PAA, 2 PCs), isolated cells (5 PAs, 2 PAAs, 2 PCs), nuclear atypia (2 PAs, 1 PAA, 2 PCs), cytoplasmic inclusions (4 PAs, 2 PCs), nucleoli (2 PCs) and mitoses (2 PCs).

CONCLUSION

Evident nucleoli and mitoses may suggest the differentiation between PA and PC. However, further investigations are required to confirm these preliminary observations.

Recurrent primary hyperparathyroidism due to Type 1 parathyromatosis

Parathyromatosis is a rare condition consisting of multiple nodules of benign hyperfunctioning parathyroid tissue scattered throughout the neck and superior mediastinum. As a potential cause of recurrent or persistent hyperparathyroidism, parathyromatosis is a challenging condition to diagnose and treat. The optimal evaluation and management of patients with parathyromatosis is not well established. The reported case involves a patient who was initially diagnosed with primary hyperparathyroidism. The diagnosis of Type 1 parathyromatosis was made after the patient developed recurrent hyperparathyroidism with hypercalcemia and osteoporosis 17 years after the initial operation and underwent two additional operations. The majority of parathyromatosis cases are diagnosed in the setting of secondary hyperparathyroidism. Consensus regarding the preoperative diagnosis and evaluation is lacking due to the paucity of cases of this rare clinical entity. Management involves complete surgical extirpation of all identifiable rests of parathyroid tissue. Intra-operative parathyroid hormone level monitoring and frozen section examination are excellent tools that could increase the rates of initial operative success. Despite this, long-term disease remission is rare, and medical therapy, including calcimimetics and bisphosphonates, may be required for postoperative or non-operative management.

The Significance of 18F-Fluorocholine-PET/CT as Localizing Imaging Technique in Patients with Primary Hyperparathyroidism and Negative Conventional Imaging

OBJECTIVE

The essential prerequisite for focused parathyroidectomy in patients with primary hyperparathyroidism (pHPT) is proper localization of all autonomic tissue. Sensitivity of conventional imaging modalities (ultrasound, ^99mTc-sestamibi scintigraphy/SPECT/CT) is influenced by different factors (i.e., size/weight and position of autonomic tissue) and decreases in the presence of a multinodular goiter. Therefore, a considerable percentage of pHPT patients have negative or equivocal localization studies before surgery. The aim of this study is to evaluate the utility of FCH-PET/CT for preoperative localization in patients with pHPT and negative/equivocal ^99mTc-sestamibi scintigraphy/SPECT/CT and/or ultrasound.

METHODS AND MEASUREMENTS

Between 2014 and 2017, a total of 39 patients with pHPT and negative/equivocal conventional imaging were referred for FCH-PET/CT. In the analysis, we included those (n = 23) who had surgery and a histopathologic workup of the lesions.

RESULTS

19 of 23 patients demonstrated no tracer uptake with ^99mTc-sestamibi scintigraphy/SPECT/CT, 6 patients had an equivocal sonographic lesion, and multinodular goiter was present in 43% (10/23). In 21 of 23 patients, hyperfunctioning parathyroid tissue was identified correctly by FCH-PET/CT [21 true positive, 1 false negative, and 1 false positive; per-patient sensitivity 95.5% (95% confidence interval {CI}, 77.2-99.9)]. 29 lesions were resected [21 true positives, 3 false negatives, 1 false positive, and 4 true negatives; per-lesion sensitivity 87.5% (95% CI, 67.6-97.3)]. All patients were classified as having surgical success according to a decrease of intraoperative parathyroid hormone of ≥50% and normalization of postoperative serum calcium levels.

CONCLUSION

Despite a high prevalence of multinodular goiter, diagnostic accuracy of FCH-PET/CT in our patient group was excellent. Therefore, FCH-PET/CT is a promising new imaging tool in patients with pHPT and negative/equivocal results by conventional imaging techniques.

Efficacy of microwave ablation for severe secondary hyperparathyroidism in subjects undergoing hemodialysis

Severe secondary hyperparathyroidism (SHPT) is a serious problem in patients undergoing hemodialysis. The efficacy and safety of microwave ablation (MWA), a minimally invasive treatment, for severe SHPT are as yet unclear. To clarify the role of MWA, we administered it to patients with severe SHPT and assessed its efficacy and safety. This was a prospective, single-center, single-arm, clinical trial. We enrolled patients with severe SHPT attending our hemodialysis center who met the inclusion and exclusion criteria. We then assessed primary outcome measures (serum concentrations of intact parathyroid hormone) and secondary outcome measures (serum concentrations of calcium and phosphorus). Twenty-six patients were enrolled in this study, 10 of whom (38.46%) were responsive to MWA and 16 (61.54%) of whom were not. The main complication was hypocalcemia (10 cases, 38.46%), which had occurred in all cases by one week after administration of MWA. Responding patients with hypocalcemia all achieved normal serum calcium concentrations within seven months and non-responding patients within three months. There were no changes in serum phosphorus concentrations after MWA in either responders or non-responders. Microwave ablation is relatively ineffective in patients with severe SHPT undergoing maintaining hemodialysis and should not be the initial therapy in such cases.

Atypical Parathyroid Adenoma Complicated with Protracted Hungry Bone Syndrome after Surgery: A Case Report and Literature Review

Hungry Bone Syndrome refers to the severe and prolonged hypocalcemia and hypophosphatemia, following parathyroidectomy in patients with hyperparathyroidism. We present the case of an eighteen-year-old woman with a four-year history of hyporexia, polydipsia, weight loss, growth retardation, and poor academic performance. The diagnostic work-up demonstrated primary hyperparathyroidism with hypercalcemia of 13.36 mg/dL, a PTH level of 2551 pg/mL, bone brown tumors, and microcalcifications within pancreas and kidneys. Neck ultrasonography revealed a parathyroid adenoma of 33 × 14 × 14 mm, also identified on (99)Tc-sestamibi scan. Bone densitometry showed decreased Z-Score values (total lumbar Z-Score of -4.2). A right hemithyroidectomy and right lower parathyroidectomy were performed. Pathological examination showed an atypical parathyroid adenoma, of 3.8 g of weight and 2.8 cm in diameter. After surgery she developed hypocalcemia with tetany and QTc interval prolongation. The patient required 3 months of oral and intravenous calcium supplementation due to Hungry Bone Syndrome (HBS). After 42 months, she is still under oral calcium. Usually HBS lasts less than 12 months. Therefore we propose the term "Protracted HBS" in patients with particularly long recovery of 1 year. We present a literature review of the diagnosis, pathophysiology, and treatment of HBS.

Clinicopathological correlates of hyperparathyroidism

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

Parathyroid adenoma in patients with Graves' disease: a report of 21 cases

Graves' disease (GD) is frequently associated with mild hypercalcemia. The hypercalcemia may be due to the activation of osteoclastic bone resorption caused by the excess thyroid hormone. In some cases of GD, the hypercalcemia can be attributable to concomitant parathyroid diseases. In this study, 21 patients with a history of GD developed parathyroid adenoma based on histology, intraoperative parathyroid hormone (IOPTH) monitoring, and other clinical features. There were 11 patients with a history of radioactive iodine therapy (RAI) for GD. The latency time of RAI was from 12 to 41 years. The case cohort was divided into two groups: patients with (group GR: 11 patients) and patients without a history of RAI (group G: 10 patients). Mean age of patients in group GR was 54.8 years compared to 62.2 years of group G (P = 0.08). There were no statistically significant differences regarding the parathyroid weight, serum calcium, and pre- and post-parathyroidectomy PTH levels. There was no histopathologic difference between the two groups. In conclusion, we report 21 cases of parathyroid adenoma in patients with Graves' disease. There may be a possible link between GD patients with a RAI history and an increased risk of parathyroid adenoma. The parathyroid adenomas showed no clinicopathological differences between GD patient with and without a history of RAI.

Parathyroid: The Pathology of Hyperparathyroidism

This review focuses on the pathologic entities associated with hyperparathyroidism in humans. A discussion of the lesions, their embryology, and pathologic features is included. Immunohistology, cytopathology, and a brief overview of molecular aspects of the lesion are included.

Oncocytic lesions of the neuroendocrine system

This paper reviews the pathologic features of lesions which are oncocytic and involve classic endocrine organs. The history of the oncocytic cell, its morphologic and ultrastructural features, and important immunohistochemical findings are reviewed. Oncocytic proliferations including non-neoplastic and neoplastic of the thyroid, parathyroid, adrenal (both cortex and medulla), and pituitary are described. Their clinical relevance, functional capacity and capability, and where appropriate, prognostic implications are discussed. Important and relevant molecular biological information is included where appropriate.