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A man in his 70s was referred to the endocrine surgery department after incidental finding of hypercalcaemia during preoperative work-up for abdominal aortic aneurysm repair. The patient reported severe fatigue and malaise with no previous history of nephrolithiasis or osteoporosis. After biochemical confirmation of primary hyperparathyroidism, localisation studies suggested multiple gland disease. Intraoperatively, three enlarged parathyroid adenomas were found and excised. Histopathological and immunohistochemical examination revealed triple water clear cell (WCC) parathyroid adenomas. Adenomas being entirely composed of WCCs are rare. In addition, triple adenomas are so rare that their existence is disputed by some authors. The present paper reports on an extremely rare case of a patient suffering from triple parathyroid adenomas composed entirely of WCCs. To our knowledge, this is the first such reported case in the English language literature.

Primary hyperparathyroidism is the third most common endocrine disease. The aim of our study was to determine long-term outcomes and risk factors for persistence in patients undergoing parathyroidectomy for primary hyperparathyroidism.Retrospective study including patients undergoing parathyroidectomy between 2009- 2019. Cure was defined as reestablishment of normal calcium homeostasis lasting a minimum of 6 months. Persistence was defined by ongoing hypercalcemia more than 6 months after surgery. Recurrent PHTP was defined by recurrence of hypercalcemia after a normocalcemic interval at more than 6 months after surgery. A more detailed analysis was performed on patients with normocalcemia and persistently elevated PTH levels after surgery. Variables independently related to persistence were analyzed by multivariate analysis.We included 212 patients. Mean age was 59 years and 83% were women. Cure was observed in 204 patients (96.2%), persistence in 8 (3.8%) and recurrence in 3 (1.4%). Four patients (1.9%) presented normocalcemia and persistently elevated PTH after surgery. All presented parathyroid pathology (2 adenomas and 2 hyperplasia). In follow-up we observed that adenoma subgroup presented one patient with CKD and one with vitamin D deficiency while in the hyperplasia subgroup two patients presented CKD. Persistence was independently associated with hyperplasia (Odds ratio=12.6, IC95%=1.28-124, p=0.030) and normal parathyroid tissue (Odds ratio=188, IC95%=9.33-379, p=0.001) on histopathological report. CONCLUSIóN: Primary hyperparathyroidism is a safe procedure in terms of morbidity and long-term outcomes. Hyperplasia and normal parathyroid tissue on histopathological report are risk factors for persistence. An interdisciplinary diagnostic and therapeutic approach is required to prevent persistence.

The coexistence of parathyroid hyperplasia and carcinoma is uncommon. Here we report findings of 99m Tc-sestamibi SPECT/CT study in a case of unilateral bifocal parathyroid carcinoma coexisting with parathyroid hyperplasia in a 49-year-old man. The images showed 4 foci of elevated activity around the thyroid. Histopathology confirmed the 2 lesions of the left side as parathyroid hyperplasia and the other 2 lesions of the right side as parathyroid carcinoma.

Parathyroid Carcinoma is a rare malignant neoplasm, accounting for less than 1% of primary hyperparathyroidism cases. Parathyroid carcinomas are characterized by markedly elevated levels of PTH, severe hypercalcemia and established target organ damage. The authors report the experience of a single centre regarding the management and outcome of patients with parathyroid carcinomas and revise relevant literature.Retrospective review of all patients with parathyroid carcinoma evaluated at a tertiary oncologic centre from 1991 until 2021.Seventeen patients were identified (10 males), with a mean age at diagnosis of 53 ± 16 years and a median follow-up of 16.5 years. Most patients presented with hypercalcemia (n = 15), with a mean serum calcium concentration of 13.5 mg/dl (9.6-16.5) and mean PTH of 1173 pg/ml (276-2500). Hyperparathyroidism-mediated organ damage was observed in most patients (n = 16), with predominant renal (n = 12) and skeletal (n = 9) complications. En bloc surgical resection was performed in nine patients. Three patients underwent adjuvant radiotherapy. Recurrence was observed in 8 cases (47.1%) after a median of 24 months following surgery and no independent predictors of recurrence were identified. The overall survival and disease specific survival at 5-year was 88% and 94%, respectively. CDC73 mutations were present in 38.5% of analysed patients and one patient was diagnosed with MEN1.Parathyroid carcinoma is associated with a significant rate of recurrence and limited effective treatment beyond initial complete surgical resection. Therefore, preoperatively high index of suspicion is paramount to optimize patient care. This is, to our knowledge, the largest Portuguese cohort published so far.

Background Juvenile primary hyperparathyroidism (PHPT) is a rare endocrine disease. Its diagnosis might be masked by clinical, biochemical, and radiological features of rickets. Case presentation A 12-year-old Sudanese boy presented with progressive lower limbs deformity and difficulty in walking for six months. It was associated with fatigability, poor appetite, and generalized bone pain. On examination, he was thin, disproportionately short and pubertal, and had bilateral genu valgum deformity. X-rays showed osteopenia and signs of rickets. Biochemical workup revealed mildly elevated serum calcium, low phosphate, high alkaline phosphatase, and high parathyroid hormone with low 25-hydroxy vitamin D3. Celiac screening, liver function test and renal profile were normal. Serum calcium rose dramatically after vitamin D therapy. Genetic testing was negative for CYP2R1 and MEN1 genes. Ultrasound neck showed left inferior parathyroid adenoma which was surgically excised. Histopathology confirmed the diagnosis of parathyroid adenoma. Postoperatively, he had hypocalcemia which was treated with calcium and alfacalcidol. Corrective surgery is planned for the genu valgum deformity which markedly improved after parathyroidectomy. Conclusion Although PHPT is extremely rare in the young population, it should be considered in patients with rickets and elevated serum calcium at baseline or after initiating vitamin D therapy.

Introduction This study aimed to evaluate the effect of sono-scintigraphic correlation on the success of minimal invasive parathyroidectomy (MIP) via surgeon performed continuous intraoperative sonographic guidance in patients operated for primary hyperparathyroidism(PHPT) without intact parathormone (PTH) measurement. Materials and methods A retrospective analysis of a prospective database was conducted to review patients who underwent MIP (July 2017-October 2019). The screened parameters were preoperative PTH level, preoperative ultrasonography (US), preoperative scintigraphy, intraoperative US, intraoperative frozen section analysis, postoperative PTH level and permanent pathology report. Intraoperative intact PTH measurement was not employed due to institutional policy. Results Preoperative US alone localized the specific side (right/left, inferior/superior) of abnormality in 54 out of 74 (72.97%) cases. Scintigraphy alone localized the specific side in 58 (78.37%) cases. The sensitivity of preoperative US and scintigraphy alone was 76.05% and 86.56%, respectively. Sono-scintigraphic discordance was present in 6 cases (8.1%) and intraoperative real-time US predicted accurate localization of adenoma in 4 (66.6%) and scintigraphy in 2 (44.4%) patients. The frozen section analysis confirmed parathyroid cells in all cases evaluated. Conclusion Sono-scintigraphic concordance with intraoperative real-time imaging increases surgical success rates in cases where MIP is planned under the circumstances of limited resources regarding unavailability of intact PTH measurement.

Ultrasonography (US) andTo evaluate the application value of contrast-enhanced ultrasound (CEUS) in the preoperative localization of microwave ablation (MWA) for primary hyperparathyroidism (PHPT).Between December 2012 and May 2021, 100 PHPT patients (34 males and 66 females; mean age, 56.31 ± 13.43 years; age range, 25-85 years) with 130 suspected parathyroid nodules were enrolled. US, CEUS, andA total of 130 nodules suspected to be of parathyroid origin from preoperative localization images were confirmed by pathological results, of which 116 were of parathyroid origin, and 14 were not of parathyroid origin. The sensitivity, specificity, accuracy, and the area under receiver operating characteristic curve of CEUS in the localization of pathological parathyroid glands were 100%, 92.86%, 99.23%, and 0.964, which were significantly higher than those of US (93.10%, 42.86%, 87.69%, and 0.680) andCEUS is a valuable preoperative localization method for PHPT patients performed MWA, especially for the patients with smaller pathological parathyroid gland and multiple glandular lesions.

Context Primary hyperparathyroidism (PHPT) results from the hypersecretion of parathyroid hormone from parathyroid tumors. A transcription factor, namely Paired box1 (PAX1), is active in parathyroid gland development. Objective We aimed to study potential epigenetic-mediated mechanism of PAX1 gene in sporadic parathyroid adenomas. Methods In parathyroid adenomas tissues, we analyzed the DNA methylation via bisulfite-specific polymerase chain reaction (BSP) and histone modifications via chromatin immunoprecipitation in regulating the differential expression of PAX1. Results The results showed that mRNA and protein expression of PAX1 was significantly reduced in parathyroid adenomas. Bisulfite sequencing demonstrated hypermethylation in the promoter region of PAX1 (35%; 14/40) and lower levels of histone 3 lysine 9 acetylation (H3K9ac) were observed on the promoter region of PAX1 (6-fold; P < .004) in parathyroid adenomas. Furthermore, upon treatment with a pharmacologic inhibitor, namely 5′aza-2 deoxycytidine, in rat parathyroid continuous cells, we found re-expression of PAX1 gene. Conclusion Our study not only reveals expression of PAX1 is epigenetically deregulated but also paves a way for clinical and therapeutic implications in patients with PHPT.

There are multiple imaging modalities in primary hyperparathyroidism. Ultrasound examination and subtraction scintigraphy are usually the first-line imaging techniques. When these results are negative or inconsistent, additional [11C]-methionine PET/CT (MET-PET/CT) or 4-dimensional computed tomography can be performed. ​This study aims to evaluate MET-PET/CT in comparison with other imaging techniques in primary hyperparathyroidism. This is a retrospective cohort study. Eighty-four patients with primary hyperparathyroidism, who underwent parathyroid surgery, were included. ​Imaging results have been correlated to the perioperative drop in parathyroid hormone level and to the pathological analysis. ​Descriptive statistics are used, supplemented with 95% Clopper–Pearson confidence intervals for sensitivity and specificity and a sub-analysis with the McNemar test on paired data only. The per-lesion sensitivity of MET-PET/CT seems higher than that of [99mTc]-sestamibi or [99mTc]-tetrofosmin and [99mTc]-pertechnetate subtraction scintigraphy. The McNemar test, on paired data only, shows significantly higher sensitivity of MET-PET/CT compared to ultrasound (p=0.039) and significantly higher specificity of ultrasound compared to subtraction scintigraphy (p=0.035).​ MET-PET/CT after inconclusive or negative ultrasound and/or subtraction scintigraphy has an additional value in 70% of the cases.​ Preoperative parathyroid hormone levels were higher in patients in whom MET-PET/CT correctly predicted the pathological parathyroid glands, compared to those where MET-PET/CT missed at least one adenoma. The same trend was seen for 4-dimensional computed tomography. In conclusion, MET-PET/CT seems a valuable imaging modality in primary hyperparathyroidism, at least as second line imaging approach, with a higher per-lesion sensitivity than ultrasound in such setting. Especially when ultrasound and/or subtraction scintigraphy are inconclusive or negative, MET-PET/CT directs the surgeon to the correct localization of the parathyroid adenoma.

Parathyroid Lipoadenoma (PLA) contains abundant mature adipose tissue and is a rare cause of hyperparathyroidism. This study aimed to investigate the clinical features of PLA in nine patients with primary hyperparathyroidism, including two men and seven women, with ages ranging from 45-84 years (median 60 years). PLA accounted for 0.5% of all parathyroid tumors during the study period. One patient presented with anorexia due to hypercalcemia; however, the other eight patients were asymptomatic. The median preoperative serum intact-parathyroid hormone (iPTH) and calcium levels were 143 pg/mL (range, 102-378) and 10.8 mg/dL (range, 10.3-11.3), respectively. PLA was difficult to identify using ultrasonography (US) as it appears as a moderately hyperechoic nodule and is difficult to distinguish from the surrounding adipose tissues. Only 33% of the lesions (three out of nine lesions) were accurately identified. However, they could be distinctly differentiated from the surrounding tissue using computed tomography (CT). All PLAs were also detected using the sesta-methoxyisobutylisonitrile single-photon emission-computed tomography (SPECT). All the patients were treated by a single gland extirpation. The median size and weight of the PLA were 14 mm (range, 10-22) and 567 mg (range, 200-1,533), respectively. In conclusion, the clinical manifestations of PLA are similar to those of ordinal parathyroid adenomas, except for their unique US and CT images. PLA should be considered as a potential etiologic factor in cases of hyperparathyroidism when the lesions are demonstrated as hyperechoic nodules or unidentified by US but detected by CT or SPECT imaging.

BackgroundPrimary hyperparathyroidism (PHPT) results from an excess of parathyroid hormone (PTH) produced from an overactive parathyroid gland. The study aimed to explore the sonographic features of parathyroid adenomas and assess the diagnostic performance of ultrasonography (US) and Tc-99m MIBI SPECT/CT for preoperative localization of parathyroid adenomas.MethodsA total of 107 patients were enrolled in this retrospective study who had PHPT and underwent parathyroidectomy. Of the 107 patients, 97 performed US and Tc-99m MIBI SPECT/CT examinations for preoperative localization of parathyroid nodules. The sensitivity and accuracy of each modality were calculated.ResultsIn this study, residual parathyroid sign and polar vascular sign were identified as characteristic US features of parathyroid adenomas. These manifestations were closely related to the size of the abnormal parathyroid lesions. Among the 108 parathyroid nodules from 97 patients with PHPT, the sensitivity and accuracy of US for locating the parathyroid nodules were significantly higher than those of Tc-99m MIBI SPECT/CT (93.0% vs. 63.0% and 88.0% vs. 63.0% respectively; χ2 = 26.224, 18.227 respectively, P 2 = 33.410, 21.587 respectively, P 2 = 0.866, 0.187 respectively, P = 0.352 and 0.665).ConclusionsUS shows significantly better sensitivity and accuracy for localization of parathyroid adenomas than Tc-99m MIBI SPECT/CT. However, US combined with Tc-99m MIBI SPECT/CT is of great clinical value in the preoperative localization of parathyroid nodules in patients with PHPT.

This study aimed to clarify the histological alterations following fine-needle aspiration for parathyroid adenoma and discuss the occurrence of diagnostic problems. Among the 392 patients with parathyroid adenoma who underwent resection, fine-needle aspiration was performed for 21 (5.1%) parathyroid adenoma nodules. Histological findings that were significantly more frequent in cases that underwent fine-needle aspiration were considered histological alterations following fine-needle aspiration for parathyroid adenoma, including the following six findings: thick fibrous capsule (71.4%), multilayered fibrous capsules (14.3%), capsular pseudo-invasion (42.9%), fibrous bands (57.1%), hemosiderin deposition (14.3%), and tumor implantation (14.3%). Eighteen parathyroid adenoma nodules (85.7%) exhibited one or more of the six findings. Tumor cells and adipocytes entrapped within the thick fibrous capsule were occasionally observed. The fibrous bands were frequently connected to the thick fibrous capsule. The number of passes, duration between fine-needle aspiration and resection, tumor size, and purpose of fine-needle aspiration were not related to the incidence of histological findings. Because of the histological alterations following fine-needle aspiration for parathyroid adenoma that can be easily mistaken for signs of atypical adenoma or parathyroid carcinoma, we recommend that the six findings be excluded from pathological findings indicating atypical adenoma or parathyroid carcinoma in patients with preoperative fine-needle aspiration.

Introduction: It is difficult to differentiate benign and malignant lesions just by histopathological evaluation due to lack of clear criteria of diagnosis. Moreover, the group of benign pathologies of parathyroids is not homogenous, and recurrence of symptoms of hyperparathyroidism after surgical management was also noted in this group. This complication is not always due to inappropriate surgical technique. The goal of this work was to find the relationship between cellular ploidy and proliferative activity of adenomas and hyperplasia of parathyroids and preoperative levels of calcium and parathormone in the serum of patients surgically treated for primary hyperparathyroidism. Material and methods: A total of 98 parathyroid glands were tested, of which 81 (82.7%) were from female patients and 17 (17.3%) from male; the age of the patients was from 22 to 82 years, with an average of 58 years. Results: In resected glands pathological evaluation showed the following results: in 53 (54.1%) adenoma was present, and in 45 (45.9%) there was hyperplasia. Sixty-seven of the samples (68.4%) were characterised as diploid and 31 (31.6%) as aneuploid. There is important positive correlation (r = 0.34595; p = 0.011) between the percentage of S-phase cells (% SPF) and calcium levels measured prior to surgical resection of adenoma. The further analysis of patients with adenoma characterised by aneuploidy proved a statistically valid, positive correlation between %SPF and ionised calcium levels in blood serum of patients both before (r = 0.7189; p = 0.003) and after the surgical treatment (r = 0.6313; p = 0.012). Conclusions: 1. Benign lesions of parathyroid with ploidy indicates their heterogeneity. 2. In aneuploid benign adenomas of parathyroid glands an increased percentage of cells in S phase (% SPF) correlates with a high level of calcium in serum pre- and post-parathyroidectomy.

Background The incidence of primary hyperparathyroidism has increased 300% in the United States in the past 30 years, and secondary hyperparathyroidism is almost universal in patients with end-stage renal disease. We assessed the presence of environmental chemicals in human hyperplastic parathyroid tumors as possible contributing factors to this increase. Methods Cryopreserved hyperplastic parathyroid tumors and normal human parathyroids were analyzed by gas chromatography and liquid chromatography coupled to ultra-high-resolution mass spectrometry, bioinformatics, and biostatistics. Results Detected environmental chemicals included polychlorinated biphenyls, polybrominated diphenyl ethers, dichloro-diphenyl-trichloroethane derivatives, and other insecticides. A total of 99% had p,p’-dichlorodiphenyldichloroethylene. More than 50% contained other environmental chemicals, and many classified as endocrine disruptors. Polychlorinated biphenyl-28 and polychlorinated biphenyl-49 levels correlated positively with parathyroid tumor mass. Polybrominated diphenyl ether-47 concentrations in tumors were inversely correlated with patients’ serum calcium levels. Cellular metabolites in pathways of purine and pyrimidine synthesis and mitochondrial energy production were associated with tumor growth and with p,p’-dichlorodiphenyldichloroethylene in primary hyperparathyroidism tumors. In normal parathyroids, p,p'-dichlorodiphenyldichloroethylene , polychlorinated biphenyl-28, polychlorinated biphenyl-74, and polychlorinated biphenyl-153, but not p,p'-dichlorodiphenyldichloroethylene or polychlorinated biphenyl-49, were detected. Conclusion Environmental chemicals are present in human parathyroid tumors and warrant detailed epidemiologic and mechanistic studies to test for causal links to the growth of human parathyroid tumors.

Background/aim The lack of specific parathyroid carcinoma (PC) biomarkers in clinical practice points out the importance of analyzing the proteomic signature of this cancer. We performed a comparative proteomic analysis of PC and parathyroid adenoma (PA) co-existing in the same patient. Patients and methods PC and PA were taken from a 63-year-old patient. Using two-dimensional differential gel electrophoresis (2D-DIGE) coupled to mass spectrometry we examined the differences between PC and PA proteins. For validation, additional PC and PA samples were obtained from 10 patients. Western blot analysis was used to validate the difference of expression observed with 2D-DIGE analysis. Bioinfomatic analysis was performed using QIAGEN's Ingenuity Pathways Analysis (IPA) to determine the predominant canonical pathways and interaction networks involved. Results Thirty-three differentially expressed proteins were identified in PC compared to PA. Among these, ubiquitin C-terminal hydrolase-L1 (UCH-L1) was highly overexpressed in PC. The result was confirmed by Western Blot analysis in additional PC samples. Conclusion Our comparative proteomic analysis of co-existing neoplasms allowed detecting specific and peculiar differences between PC and PA overcoming population biological variability.

BACKGROUND: Primary hyperparathyroidism (PHPT) results from excessive secretion of parathyroid hormone from parathyroid tumors. Differentiating parathyroid tumors can be challenging before operation. OBJECTIVES: To differentiate parathyroid carcinoma from benign tumors in patients with PHPT by the application of ultrasound and biochemical parameters. METHODS: This study is a retrospective study. The study enrolled 17 patients with parathyroid carcinoma (PC) and 57 patients with parathyroid adenoma (PA), confirmed by postoperative pathology, between September 2010 and July 2017. This study retrospectively compared the ultrasonic features of the tumors included echotexture, maximum lesion diameter, shape, margin, blood flow inside the mass, intralesional calcifications, cysts in the mass, and biochemical parameters included serum calcium, phosphorus, parathyroid hormone (PTH), alkaline phosphatase (ALP) levels, gender distribution and age of patients between patients with PC and those with PA. RESULTS: In the US images, the two groups showed significant differences in heterogeneity, the appearance of a taller-than-wide shape, irregular or lobulated margins, and intralesional calcifications (p #x003E;> #x200A;0.05). The mean PTH levels were significantly different between the two groups (p #x003E;> #x200A;0.05). There were significant differences to distinguish PC from PA in calcifications in mass or/and taller-than-wide shape combine with PTH > #x003E;> #x200A;1000 pg/mL (p #x003E;> #x200A;0.05). CONCLUSION: Ultrasound features especially intralesional calcifications and taller-than-wide shape combine with an extremely high serum PTH (>1000 pg/mL) are helpful in differentiating between benign and parathyroid tumors in patients with PHPT.

Looking for the Outsider A 44-year-old man presented with fatigue, unintentional weight loss, and a 2-year history of hip and chest-wall pain. He had earlier presented with acute right clavicle pai...

A 71-year-old man complained of nausea and loss of appetite for eight months prior to admission. He was transported to a hospital with disorientation and diagnosed with primary hyperparathyroidism by laboratory examinations. However, ultrasonography, computed tomography, and technetium-99m labeled methoxyisobutyl isonitrile (99mTc-MIBI) with single-photon emission computed tomography did not yield definite results. In contrast, somatostatin receptor scintigraphy successfully identified the lesion responsible for the over-secretion of parathyroid hormone within the middle mediastinum. The tumor was successfully resected by surgery, and a histopathological analysis confirmed the parathyroid adenoma nature of the tumor.

A successful focused surgical approach in primary hyperparathyroidism (pHPT) relies on accurate preoperative localization of the parathyroid adenoma (PA). Most often, ultrasound is followed by [A single-center retrospective analysis of patients with pHPT from 01/2005 to 08/2021 was carried out followed by evaluation of the preoperative imaging modalities to localize PA. The localization of the PA had to be confirmed intraoperatively by the fresh frozen section and significant dropping of the intraoperative parathyroid hormone (PTH) levels.From 658 patients diagnosed with pHPT, 30 patients were excluded from the analysis because of surgery for recurrent or persistent disease. Median age of patients was 58.0 (13-93) years and 71% were female. Neck ultrasound was carried out in 91.7% and localized a PA in 76.6%. In 23.4% (135/576) of the patients, preoperative neck ultrasound did not detect a PA. In this group, [[

Background Giant parathyroid adenoma is a type of parathyroid adenoma weighing > 3.5 g and having a size of more than 2 cm. Case presentation This report describes giant primary parathyroid adenoma with reference to the literature. We report the case of a 48-year-old Persian man referred to the clinic with knee and lower back pain. He had a history of mitral valve replacement and several episodes of bilateral nephrolithiasis. After a thorough assessment, a neck mass with a possible thyroid origin was detected, but further assessment showed it was of parathyroid origin. The resected mass was 9 × 6× 4 cm and weighed 122 g, and histopathology showed a giant parathyroid adenoma. Conclusion Giant parathyroid adenomas that weigh more than 110 g and are larger than 8 cm can lead to significant hypercalcemia. Despite giant parathyroid adenomas and high parathyroid hormone levels, a calcium crisis may not always occur in these patients, and the masses may be initially misdiagnosed as a thyroid mass.

Parathyroid carcinoma (PC) is a rare type of endocrine cancer. Recurrence and metastasis are common after surgery, and refractory hypercalcemia often leads to a poor prognosis. However, there are currently no specific strategies for PC recurrence. We herein report a 61-year-old Japanese man with metastatic PC who was treated with sorafenib, a multikinase inhibitor. In this case, the serum calcium level was under control for 10 months after the initiation of sorafenib. This case suggests that combination therapy with sorafenib, evocalcet, and denosumab may be an alternative, stronger management option for refractory hypercalcemia in recurrent PC.

Parathyroid carcinoma is a rare diagnosis. The association of clinical and pathologic factors as well as treatment on overall survival (OS) is not well established.A retrospective review of patients with parathyroid carcinoma was performed using the National Cancer Database for patients diagnosed from 2004 through 2017. Clinical and demographic variables were assessed. A Cox proportional hazards model was used to assess for factors associated with survival. OS rates were determined for 5 and 10 y.Data for 1057 patients were analyzed. The mean age at diagnosis was 57.5 y (standard deviation [SD] 14.0), and 542 (51.3%) were male. The median tumor size was 2.7 cm (interquartile range 2.0-3.7 cm). For the extent of surgery, 38 (3.6%) had no surgery, 568 (53.7%) had incomplete resection, 359 (34.0%) had complete resection, 58 (5.5%) had radical resection, and 34 (3.2%) did not have specified and were not used in the Cox proportional hazard regression model. For the cohort, 488 (46.2%) had lymph nodes resected with a mean of 5.5 (SD 6.6) removed. Of these, 32 (8.3%) had nodal metastases with one to six positive nodes. For adjuvant therapy, 159 (15.0%) had external beam radiation with a mean dose of 5463 cGy (SD 1464). Overall, 214 patients died (21.55%), and the estimated 5- and 10-y OS were 82.9% and 57.0%, respectively. In a Cox proportional hazard regression model, age at diagnosis as a continuous variable with hazard ratio (HR) 1.04, 95% confidence interval (CI) 1.01-1.06, P = 0.003, and extent of surgery as a categorical variable with no surgery as the referent group: incomplete surgery HR 0.05, 95% CI 0.01-0.19, P 0.001; complete surgery HR 0.04, 95% CI 0.01-0.19, P 0.001; radical surgery HR 0.10, 95% CI 0.02-0.45, P 0.001; and tumor size as a continuous variable was not associated with OS with an HR of 1.00, 95% CI 0.99-1.00, P = 0.738.Patient age and extent of surgery are modestly associated with survival for parathyroid carcinoma but not patient sex, nodal metastases, or adjuvant therapy in this cohort.

A 77-year-old man with a case of hyperthyroidism with high parathyroid hormone (41 pmol/L), low vitamin D, and normal thyroid-stimulating hormone. The SPECT/CT fused images confirmed the evidence of retrotracheal hyperdense mass approximately 1.0 cm of diameter below the lower pole of the right thyroid lobe with increased uptake, highly suggestive of typical parathyroid adenoma. The most significant point is that there was an incidental finding: high focal uptake in the sellar/suprasellar region corresponding to heterogenous soft tissue lesion suspicious for pituitary adenoma. According to the previous scans, nuclear medicine, CT scan, and the MRI scan indicated pituitary adenoma.

BackgroundSingle parathyroid adenoma is the main cause of primary hyperparathyroidism (PHPT), with surgery remaining the gold standard for its treatment. The ability to preoperatively predict the parathyroid adenoma size and could facilitate the decision about the extent of surgical exploration. It is reasonable to hypothesize that the perioperative levels of PHPT-related variables (i.e. calcium, parathormone, phosphate) may predict the adenoma weight or/and demonstrate whether the adenoma is successfully removed or not. Aim of this study is to explore the relationship between perioperative biochemical values and adenoma weight. Secondarily, we investigated the relationship between adenoma weight and uni-/bilateral neck exploration.MethodsRetrospective study of all patients undergone surgery for primary hyperparathyroidism due to single adenoma in a tertiary university hospital in Germany during a 6-year period. Following variables were analyzed: preoperative serum calcium, phosphorus and parathormone, intraoperative parathormone before and after adenoma excision, intraoperative PTH decrease, postoperative serum calcium and parathormone (PTHpostop—pg/ml), calcium and PTH decrease. Bivariate correlations were calculated by the Spearman's correlation test at the 95% significance level.ResultsA total of 339 patients were included in the study. The median age of the patients was 60 years (range 21–90) and 77% were females. The median adenoma weight was 1 g (range 0.1–11). Adenoma weight correlated strong with maximum adenoma diameter (r = 0.72, p weight 0.8 g vs 1.1 g, p = 0.005).ConclusionsWe conclude that preoperative PTH levels may only serve as an approximate guide to adenoma weight, as direct preoperative prediction is not possible. Serum calcium levels, PTH and calcium decrease correlate only weak with adenoma weight. Patients who require bilateral neck exploration, have significantly (20–25%) lighter adenomas.

Primary hyperparathyroidism (PHPT), a third common endocrine disorder, varies from asymptomatic disease, mostly seen in the West where routine biochemical screening is practiced, to the classical symptomatic disease mostly seen in the Eastern countries. We aimed to compare the demographic, clinical, biochemical measurements in patients with asymptomatic and symptomatic PHPT from the Indian PHPT registry.Data of PHPT patients from the last 25 years (1995-2019) were analyzed for demographic, clinical presentation and biochemical measurements, and compared these characteristics between asymptomatic and symptomatic PHPT patients.Of the 554 patients, 54 (10%) patients had asymptomatic PHPT. There was a sharp rise in the proportion of asymptomatic PHPT patients of 3% in the first decade to 13% in the second decade of the century (p = 0.003). Patients with asymptomatic PHPT were significantly older (50 vs. 42 years; p 0.0001) and had higher mean body mass index (27.8 vs. 23.5 kg/mAlthough symptomatic PHPT is still most prevalent ( 90%) in India with higher indices of the disease and tumor weights, there is a progressive rise in the prevalence of asymptomatic PHPT patients in the last decade. Improvements in calcium and vitamin D nutrition might account for this change as in the Western series.

Background We aimed to determine the indication of fine‐needle aspiration (FNA) for parathyroid adenoma (PA)‐suspected nodules and the cytological features of PA, and to discuss the ancillary techniques for diagnostic confirmation. Method Clinical, cytological, and histological examinations of 15 PA patients (4.0% of all PA resected patients) were conducted through FNA on 16 nodules. We also examined the cytological preparations of 10 follicular neoplasms (FNs) and 10 poorly differentiated thyroid carcinomas (PDTCs). Results FNA was performed to detect PA in nine (56.3%) nodules. The remaining seven (43.8%) nodules underwent FNA for lesions considered as thyroid nodules or lymph nodes. The levels of parathyroid hormone (PTH) in the aspiration needle washout fluid were observably high, except for that from one nodule with unsatisfactory FNA. Cytologically, the incidences of wedge pattern (86.7%) and salt and pepper chromatin (86.7%) in PAs were significantly higher than in FNs and PDTCs. In contrast, the appearance of colloid globules and nuclear grooves was less frequent than that of FNs and PDTCs. GATA‐3 expression was intense in all PAs that immunocytochemistry were performed. Histologically, capsular invasion and/or laceration, tumor seeding, granulation tissue, and fibrosis were observed. Conclusions When PA localization is unusual or inconclusive despite extensive imaging, FNA may be performed. We asserted that wedge pattern, salt and pepper chromatin, and the absence of colloid globules and nuclear grooves are diagnostic cytological indicators of PA rather than of FN or PDTC. We recommend PTH measurements using needle washout fluid for PA‐suspected nodules, and immunocytochemistry with the GATA‐3 antibody for cytologically PA‐suspected nodules.

Background: Frozen section of excised tissue is used to confirm removal of the etiology of primary hyperparathyroidism in the current era of intraoperative parathyroid hormone measurement and provides safeguards for surgeons. We recently reported that the aspartate aminotransferase (AST)/lactate dehydrogenase (LD) ratio in tissue suspension can accurately distinguish normal parathyroid tissue from other tissues. Therefore, we hypothesized that this ratio may also be applied to distinguish hyperfunctioning parathyroid tissue (HPT) from other tissues. Methods: We prospectively analyzed 22 patients who underwent parathyroidectomy for primary hyperparathyroidism (benign, 21; malignant, 1) from July 2018 to October 2019. In total, 27 specimens were examined. Approximately 1 mm3 of minced HPT as confirmed by frozen sections was suspended in 1 mL of normal saline and AST and LD levels were measured. The AST/LD ratios of other tissues (normal parathyroid tissue, thyroid gland, adipose tissue, and others; n = 94) were obtained from our previous report. Results: The AST/LD ratio of benign HPT was consistently higher than that of other tissues (P, ファイル公開日: 2021/08/01

Parathyroid carcinoma (PC) is a rare endocrine malignancy with poor outcomes. Although some mutations such as CDC73 have been found in patients, the molecular mechanism of PC still needs extensive data to clarify. Whole-genome sequencing (WGS) was performed with frozen samples from 23 PC patients. Peripheral leukocytes were collected from 14 patients and served as controls. Somatic and germline gene alterations, copy number abnormalities and structural variants were detected. Inactivating CDC73 mutations were identified in 39.1% of patients, but only one germline inactivating mutation was found. Other cancer-related mutations identified in more than one case were MAF (2/23), NEB (6/23), NCOR1 (2/23), TTK (2/23), GRIN3A (4/23), TRIO (2/23), MAP1B (2/23), TJP2 (2/23) and FAM20A (2/23). In the seven wild-type CDC73 samples, the mutated genes were enriched in pathways involving antigen presentation, allograft rejection or autoimmune disease. More copy number variants were found in patients with cancer recurrence (P = .006) and CDC73 mutations (P = .022) than in those without these characteristics. PIK3CA loss was found in one sample, which also harboured a CDC73 mutation. Gene alterations in the PI3K/AKT/mTOR pathway were found in 78.3% (18/23) of tumours. The most prominent cancer-predisposing mutations were PDE4DIP (15/23), MAP3K1 (13/23) and CDC42EP1 (10/23). In conclusion, the PI3K/AKT/mTOR pathway may be pivotal in PC. CDC73 mutation correlated with an increased mutational burden and tumour relapse. PC patients with wild-type CDC73 harboured mutations relevant to antigen presentation and autoimmune diseases. A molecular classification based on the CDC73 mutation may help to manage follow-up and therapy for PC patients.

Minimal invasive techniques in endocrine surgery were lately adopted by surgical teams due to significant complications related to inadequate operative space and high risk of injuring crucial surrounding structures, such as vessels and nerves. Over the last years, technological improvements introduced robotic systems and approaches in endocrine surgery. Several case reports and series have described the safety and efficacy of these procedures such as robotic thyroidectomy and robotic parathyroidectomy. In the current review, we included 15 studies which described robotic-assisted parathyroidectomy for cervical parathyroid adenoma, in patients diagnosed with primary hyperparathyroidism or secondary hyperparathyroidism. No significant negative short-term outcomes were observed, in terms of postoperative complications, such as temporary or permanent injury of RLN, postoperative hypoparathyroidism and blood loss. The cosmetic result was, definitely, superior in comparison to conventional open parathyroidectomy. Despite the fact that RAP is an effective and curative method for patients with PHPT or secondary hyperparathyroidism, there are no available randomized clinical trials to establish this modern procedure as a gold-standard treatment strategy for these patients.

Summary: Background: Primary hyperparathyroidism is a prevalent disease with proven benefits for appropriately selected patients who undergo parathyroidectomy. The ability to accurately predict expected single adenoma gland weight as the cause based on preoperative biochemical tests could improve cure rates in a minimally invasive approach. Objective: To assess the correlation between parathyroid weight and preoperative parathyroid hormone and calcium levels in patients with primary hyperparathyroidism with a solitary adenoma and determine if these could be used to predict expected parathyroid weight. Methods: Patients with primary hyperparathyroidism who underwent curative parathyroidectomy from 2013 to 2018 was retrospectively analysed. Results: There is a strong positive correlation r = 0.602 between preoperative PTH levels with respect to parathyroid weight (p

Introduction Bilateral giant parathyroid adenoma in the absence of multiple endocrine neoplasia (MEN) type 1 is extremely rare and literature on this subject is limited. Case history A 79-year-old man presented with acute kidney injury secondary to hypercalcaemia. Blood test results indicated primary hyperparathyroidism. Ultrasonography revealed bilateral parathyroid adenomas measuring 19.4mm x 19.5mm x 18.8mm (left) and 15.2mm x 18.3mm x 19.6mm (left) whereas on computed tomography, the measurements were 31mm x 20mm (left) and 30mm x 14mm (right). Intraoperatively, giant adenomas measuring 50mm x 25mm x 12mm (left, weighing 8.101g) and 48mm x 22mm x 10mm (right, weighing 7.339g) were identified and excised. Parathyroid hormone level dropped from 44.6pmol/l preoperatively to 8.9pmol/l postoperatively (normal range 1.3–7.6pmol/l). The patient was discharged with no complications. Conclusions We report a rare phenomenon where bilateral giant parathyroid adenoma occurred in the absence of MEN type 1. It highlights the importance of cross-sectional imaging in delineating the anatomy of adenomas as their size can be grossly underestimated by ultrasonography alone.

The goal of this study was to analyse the kinetics of corrected calcemia levels (Cac) after parathyroid excision and to determine the percentage of variation (ΔCa) in the initial hours after surgery, in order to entertain an early discharge.Were included in this study, patients undergoing operation for parathyroid adenoma responsible for primary hyperparathyroidism (PHP). The Cac was measure preoperatively and four hours after surgery, and then every day until patient discharge. Group A included patients for whom the Cac was inferior to 2.2mmol/L at least once postoperatively while group B included patients for whom the Cac was always equal or superior to 2.2mmol/L. The ΔCa represented the percentage of the fall in postoperative Cac with respect to preoperative Cac.Between 2010 and 2017, 156 patients fulfilled the inclusion criteria (women 80.8%, [sex ratio 1:4], median age 64 years old). Preoperative Cac was statistically significantly lower in group A compared to group B (2.67 vs. 2.82mmol/L; P0.0001). In total, 9.6% of patients had calcium supplementation for hypocalcemia, symptomatic or not. Postoperative Cac reached its nadir value on postoperative day 2. At four hours postoperative, the risk of postoperative calcelmia falling below 2.2mmol/L appeared when the ΔCa was superior to 6% with a sensitivity of 92.9% and a negative predictive value of 97.4%.After excision of a parathyroid adenoma for PHP, the Cac falls rapidly and reaches its nadir value on day 2. If the fall in calcemia is less than 6% four hours after surgery (vs. preoperative level), early discharge within the framework of ambulatory surgery is possible.

Objective In the past few years,F-18-fluorocholine PET/CT has been established as a promising imaging technique for preoperative localization of parathyroid adenomas, but the optimal time point to start PET/CT acquisition after tracer injection is yet unknown. The aim of the present study was to assess the optimal time frame to acquire the PET/CT images and to evaluate the ability of dynamic imaging to differentiate parathyroid adenomas from active lymph nodes, a common cause for false-positive scan results. Patients and methods Patients with primary hyperparathyroidism who had undergone a dynamic(18)F-fluorocholine PET/CT positive for parathyroid disease and who subsequently underwent successful parathyroidectomy were retrospectively included in this study. On the 20 minutes dynamic images, standardized uptake value measurements were acquired per 1 minute frame for the parathyroid adenoma, the thyroid gland, blood pool activity, and, if present, lymph node activity. Results A total of 101 patients were included in this study. Time-activity curves showed a decrease of activity in parathyroid and thyroid glands, with faster wash-out from the thyroid gland and on average a stable, lower activity in lymph nodes. Blood pool activity was particularly present in the first 2 minutes. Differentiation of a parathyroid adenoma from active lymph nodes was best before 5 minutes, but no definitive cutoff value could be determined. Differentiation of a parathyroid adenoma from the thyroid gland was best after 10 minutes. Conclusion Dynamic imaging starting at the early time point of 2 minutes after injection of(18)F-fluorocholine is useful for characterization of hyperfunctioning parathyroid glands.

Introduction Hypercalcaemic crisis is a rare manifestation of hyperparathyroidism and occurs in 1.6–6% of patients with primary hyperparathyroidism (pHPT). Although such high serum calcium levels (>14mg/dl) are attributed to malignancy, it is also associated with benign disease of the parathyroid glands. The aim of this study was to evaluate the clinical features and treatment modalities of patients with severe hypercalcaemia who underwent surgery for pHPT. Methods The medical records of 537 patients who underwent parathyroidectomy in our department for pHPT between 2005 and 2019 were reviewed retrospectively. Twenty-four (4.4%) of the patients were described as having severe hypercalcaemia. Results Among 24 patients, 71% were female and the mean age was 55.7 years (range: 40–71 years). The mean serum calcium level at time of diagnosis was 15.9mg/dl (range: 14–22.7mg/dl). According to postoperative pathology reports, solitary adenoma, parathyroid cancer and parathyromatosis were diagnosed with the rates of 87.5%, 8.3% and 4.1% respectively. The mean weight of the solitary parathyroid lesions was 14.9g (standard deviation: 8.9g, range: 4–38g). The mean longest diameter was 2.87cm (standard deviation: 1.4cm, range: 1–5.5cm). Serum calcium levels were within the normal range on the first postoperative day in 75% of the cases. Conclusions Severe hypercalcaemia is a rare but urgent condition of pHPT and requires prompt management. Accelerated surgery after adequate medical treatment should be performed. It is important to emphasise that giant adenoma, which is a benign disease, may be a more common cause of severe hypercalcaemia than carcinoma, unlike previously thought.

A reticulin staining pattern (RSP) can be used for the differential diagnosis of endocrine gland lesions, as in the adrenal and hypophysis glands. We aimed to use RSP for the differential diagnosis of parathyroid gland lesions. In this study, we evaluated 97 parathyroid lesions in 85 patients, as well as 29 normal parathyroid glands. All sections were stained with a silver impregnation-based kit for the reticulin stain. The RSPs were classified as short thick fiber-, anastomosing- and nodular/alveolar-pattern. The dominant pattern was accepted as being greater than 50% in each section. Short thick fibers and anastomosing and nodular RSPs were seen in adenomas, but there was no alveolar pattern. Although nodular/alveolar patterns were seen in focal areas in hyperplasia, they never became the dominant pattern. Nodular dominant RSPs were seen in adenomas; however, nodular RSPs were not seen in hyperplasia in a dominant pattern (p = 0.049). While short thick fibers were not seen in normal glands, they could be seen in adenomas (p

Objective To assess the diagnostic performance of neck ultrasound examination performed by endocrinologists to locate parathyroid adenomas in patients with primary hyperparathyroidism (PHPT). Methodology A retrospective observational study in 135 patients (mean age, 60.0 ± 12.3 years; 74.8% females) seen at endocrinology for PHPT (mean calcium level, 11.3 ± 1.2 mg/dl and mean PTH level, 240.4 ± 346.8 pg/ml) who underwent neck ultrasound examinations at the endocrinology department. 99mTc-MIBI parathyroid scintigraphy was performed before surgery in all patients. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated in surgical patients. Results Ninety-eight patients underwent surgery for PHPT and 97.8% were cured at 6 months. Parathyroid ultrasound had a sensitivity of 85% (95% CI: 75.7%–91.2%) and a positive predictive value (PPV) of 95.2% (95% CI: 87.5%–98.4%) to locate parathyroid adenomas 1.7 ± 0.9 cm in maximum diameter (69.4% in smaller glands), showing a high correlation (r = 0.661 and r = 0.716) with maximum diameter and volume of the excised adenoma. Sixty percent of patients had nodular thyroid disease (64.2% bilateral nodules with mean maximum diameter of 1.5 ± 0.9 cm), and thyroidectomy was performed in 31.6%. The highest diagnostic performance was seen with a combination of neck ultrasound and 99mTc-MIBI scintigraphy (sensitivity: 96.8% and PPV: 95.8%). Conclusion In our area, parathyroid adenoma localization with ultrasound performed by endocrinologists has a high diagnostic yield and allows for detecting nodular thyroid disease in 60% of patients.

OBJECTIVEMultiple endocrine neoplasia type 1 (MEN1) is a rare, autosomal-dominant tumor disorder characterized by the development of pituitary tumors and other endocrine neoplasms. Diagnosis is made clinically based on the development of 2 or more canonical lesions (parathyroid gland, anterior pituitary, and enteropancreatic tumors) or in family members of a patient with a clinical diagnosis of MEN1 and the occurrence of one of the MEN1-associated tumors. The goal of this study was to characterize pituitary tumors arising in the setting of MEN1 at a single institution. The probability of tumor progression and the likelihood of surgical intervention in patients with asymptomatic nonfunctional pituitary adenomas were also analyzed.METHODSA retrospective review of a prospectively maintained institutional database was performed for patients with MEN1 diagnosed from 1970 to 2017. Data included patient demographics, tumor characteristics, treatment strategies, and outcomes.RESULTSA review of the database identified 268 patients diagnosed with MEN1, of whom 158 (59%) were female. Among the 268 patients, 139 (51.8%) had pituitary adenomas. There was a higher prevalence in women than in men (65% vs 35%, p < 0.005). Functional adenomas (57%) were more common. Prolactin-secreting adenomas were the most common functional tumors. Macroadenomas were seen in 27% of patients and were more likely to be symptomatic and locally aggressive (p < 0.001). Forty-nine patients (35%) underwent transsphenoidal resection at some point during their disease course. In 52 patients who were initially observed with MEN1 asymptomatic nonfunctional adenomas, only 5 (10%) progressed to need surgery. In MEN1 patients, an initial parathyroid lesion is most likely followed in order by pituitary, pancreatic, adrenal, and, finally, rare carcinoid tumors.CONCLUSIONSAsymptomatic nonfunctional pituitary adenomas in patients with MEN1 may be followed safely with MRI. In this series, parathyroid tumors developed at the lowest median age of all cardinal tumors, and development of additional cardinal MEN1 lesions followed a predictable pattern. This pattern of disease progression could have significant implications for disease surveillance in clinical practice and may help to target clinical resources to the lesions most likely to develop next. This may aid with early detection and treatment and warrants further study.

Parathyroid carcinoma (PC) is an endocrine malignancy with a poor prognosis. The tumour immune microenvironment is a critical factor influencing the outcomes of multiple cancer types. However, knowledge of the immune microenvironment in PC remains limited. The intratumoural density of immunocytes and the Ki-67 index were evaluated immunohistochemically in 51 PC patient samples and were compared with clinicopathological features and parafibromin staining results. The Kaplan–Meier method and Cox proportional hazards analysis were used to estimate the effects of these variables on clinical outcomes. Intratumoural immunocyte density was not correlated with age, gender, urolithiasis, or palpation of a neck mass. The Ki-67 index was correlated with the intratumoural density of CD3+ cells (P = 0.022) and CD8+ cells (P = 0.021) and serum calcium levels (P = 0.022). In the intratumoural area of primary foci, Kaplan–Meier method showed that the risk factors associated with recurrence/metastasis were a low density of CD3+ (P = 0.017), CD8+ (P = 0.019) and CD45+ cells (P = 0.047), a high density of CD163+ cells (P = 0.003) and a high Ki-67 index (P = 0.004). Cox regression multivariate analysis revealed that CD163+ cell density (hazard ratio (HR) 16.19, 95% confidence interval (CI) 1.99—131.66; P = 0.009) and CD8+ cell density (HR 0.13, 95% CI 0.02—0.76, P = 0.024) were independent factors associated with PC relapse. The immune microenvironment is an important factor influencing the relapse of PC. The intratumoural density of CD3+, CD8+, CD45+, and CD163+ immunocytes was correlated with disease-free survival (DFS) in patients with PC. Immunotherapy based on T lymphocytes or tumour-associated macrophages may be a promising treatment strategy.

Parathyroid lipoadenomas (PLAs) are rare tumors, and case descriptions are limited, 50% fat on histologic examination with preoperative evidence of primary hyperparathyroidism (PHPT). A total of 8 bona fide PLA cases and 2 equivocal PLAs (close to 50% fat) were included. As approximately 4000 conventional parathyroid adenomas were diagnosed at our department during the same time interval, the prevalence of PLA was 0.20%. PLA patients were predominately female (63%) and presented with classical PHPT-related symptoms. Majority of cases were successfully located preoperatively and had an average tumor weight of 445 mg. Histologically, all PLAs consisted of > 50% mature adipose tissue, except a single case with brown fat. Of note, PLA patients exhibited a body mass index in line with PHPT patients in general, but a relatively high, near-significant prevalence of arterial hypertension was observed when compared to tumors with less fat (P = 0.0584). Future studies on this finding might be warranted. To summarize, we present one of the largest institutional PLA case series to date, and conclude that PLAs are rare, sporadic tumors mirroring many clinical aspects of conventional adenomas—with a potential coupling to hypertension worthy of follow-up studies. Electronic supplementary material The online version of this article (10.1007/s12022-020-09616-3) contains supplementary material, which is available to authorized users.

AIM To identify the differences between ultrasound (US) features of parathyroid carcinoma (PC) and benign parathyroid (BP) lesions in patients with primary hyperparathyroidism (PHPT). MATERIAL AND METHODS Twenty-one patients with PC and 64 consecutive patients with BP, whose diagnoses were confirmed at surgery, were enrolled from January 2013 to December 2018. The US features, demographic, clinical, and biochemical characteristics of the two groups were compared retrospectively. RESULTS There are no significant differences between the patients with PC and BP regarding mean age or mean ionized calcium levels but differences were seen in sex distribution and mean parathyroid hormone (PTH) levels. On US imaging, PC significantly exhibited higher incidences of larger size and higher depth/width (D/W) ratio, heterogeneous echotexture, irregular shape, non-circumscribed margin, intra-nodular calcifications, indistinct border, cystic change, and the presence of suspicious lymph nodes compared to BP lesions. CONCLUSION Preoperative ultrasonography is helpful to differentiate PC and BP. Patients with PC are differentiated from BP by their sex distribution, mean PTH levels, and major US characteristics: larger size, higher D/W ratio, heterogeneous echotexture, irregular shape, non-circumscribed margin, indistinct border, intra-nodular calcifications, cystic change, and the presence of suspicious lymph nodes.

A 77-year-old man with a history of hypertension, prostate hyperplasia, and urolithiasis was admitted for acute kidney injury caused by hypercalcemia. Neck ultrasonography showed a large cyst adjacent to the right lower thyroid lobe. Although a 99mtechnetium sestamibi scan was negative, an extremely high intracystic intact parathyroid hormone level suggested that the cyst had a parathyroid origin and that a functional parathyroid cyst was present. Immunohistochemical staining for the calcium-sensing receptor (CaSR) after right lower parathyroidectomy revealed CaSR-positive cells lining the cyst, indicating that the functional parathyroid cyst had originated from the hemorrhagic degeneration of a parathyroid adenoma.