Radiofrequency Ablation of Parathyroid Adenoma: Results of a Retrospective Analysis of 60 Patients.

PURPOSE: To present the effectiveness and safety of radiofrequency ablation (RFA) in parathyroid adenoma (PTA). MATERIALS AND METHODS: In this retrospective study, 60 patients with a single PTA were evaluated for changes in biochemical and ultrasonographic features up to 6 months after RFA of the lesion. Adenomas were ablated with an alternative technique so called "Nik jet dissection" which incorporates full hydrodissection and polar artery coagulation. Complications as well as the variations in biochemical data and nodule volumes were analyzed between baseline measurements and at each follow-up interval data (first day, 1, 3, and 6 months after ablation) were analyzed. RESULTS: A significant reduction in serum intact parathyroid hormone and calcium levels was observed 6 months after ablation, with a mean difference of - 83.4 ± 104.1 pg/mL, p < 0.001, and - 0.29 ± 0.22 mmol/L, p < 0.001, respectively. Serum phosphorus levels increased significantly with a mean difference of 0.09 ± 0.19 mmol/L, p = 0.040 at the end of the follow up. We observed a significant volume reduction rate of parathyroid adenomas with 89 ± 20.8 percent, p < 0.001. Also, 51% of adenomas disappeared at the end of the follow up. In this study, two cases of hematoma and one case of transient hoarseness (grade 1 of the CIRSE classification) were encountered. CONCLUSION: Our study showed that RFA with the alternative technique, called "Nik jet dissection" is a safe and effective modality in management of PTA. Therefore, we suggest expanding the indications for RFA in PTA management, especially when surgery is not feasible. LEVEL OF EVIDENCE: Level 3, Local non-random sample.

Thoracoscopic treatment of mediastinal ectopic parathyroid adenomas: a Latinamerica experience case series and literature review.

BACKGROUND: Hyperparathyroidism (HPT) is a disease caused by hypersecretion of one or more parathyroid glands, it can be associated with ectopic mediastinal parathyroid glands (MEPA) in 2% of cases. The use of video-assisted thoracoscopic surgery (VATS) for the surgical resection of these glands is a safe, cost-effective, and low morbidity option for patients with MEPA. We report a case series of patients with this disease managed with VATS, the first in Mexico and Latinamerica. METHODS: From 2008 to 2022, a retrospective study involving patients with MEPA and treated by VATS approach was performed in a tertiary hospital in Mexico city. Relevant biochemical and clinical variables such as imaging studies, pre and postoperative laboratory results, surgical strategy, outcomes and pathological analysis were analyzed. RESULTS: Four cases of mediastinal parathyroid adenomas causing HPT were included. All patients were female with a median age of 52.5 years-old (range 46-59 years), half of the patients had primary HPT and the others tertiary HPT after kidney transplant. 75% of cases had a MEPA in the medium mediastinum, all had a preoperative positive SPECT-CT 99mTc Sestamibi scan. Mean preoperative PTH was 621.3pg/mL (182-1382pg/mL). All patients successfully underwent parathyroidectomy with a VATS approach, no deaths were reported. CONCLUSIONS: VATS is a minimally invasive surgery that provides adequate access to mediastinal located glands, optimal visualization of mediastinal structures and has a high resection success rate with less complications and morbidity than open approaches.

Use of [18F]fluorocholine PET/CT in the detection of primary hyperparathyroidism in paediatrics: a case report.

OBJECTIVES: The most common cause of primary hyperparathyroidism (PPH) in children is a parathyroid adenoma. Among this population, PPH exhibits higher levels of morbidity, severity and target organ involvement compared to adults. When there is suspicion of PPH, cervical ultrasound and 99mTc-sestamibi SPECT/CT are the imaging test traditionally indicated. Among adults, the use of [18F]fluorocholine PET/CT has shown a higher sensitivity than ultrasound and [99mTc]sestamibi SPECT/CT, leading to an expanding adoption in recent years. However, its role in paediatrics has not been clearly defined yet. CASE PRESENTATION: The patient is an adolescent female aged 13 years presented with lithiasis. The analytical study revealed elevated PTH, hipovitaminosis D, hypercalcaemia and hypophosphataemia. Due to the suspicion of PPH, cervical ultrasound and 99mTc-sestamibi SPECT/C were performed, failing to identify hyperfunctioning parathyroid glands. We proceeded to carry out a [18F]fluorocholine PET/CT where a hypermetabolic nodular image was identified, compatible with a hyperfunctioning parathyroid adenoma. The patient underwent surgery, resulting in the normalisation of PTH levels. Pathological anatomy confirmed the presence of a parathyroid adenoma. CONCLUSIONS: In cases where conventional imaging tests yield negative results or discrepancies, we suggest the possibility of the use of [18F]fluorocholine PET/CT for the detection of hyperfunctioning parathyroid adenomas.

Imaging features and surgical management of giant parathyroid adenoma with autoinfarction.

Autoinfarction of a parathyroid adenoma can have an atypical clinicoradiologic features that can mimic an inflammatory process or malignancy. In addition, the associated fibrosis makes surgical resection more challenging than for regular parathyroid adenomas. The implications of these findings are that while autoinfarction of parathyroid adenomas is a rare phenomenon, this entity should be considered when there are heterogeneous and cystic components on imaging in patients without hypercalcemia. Ultimately, histopathology is necessary for definitive diagnosis.

A case report of mediastinal parathyroid carcinoma in a chronic kidney disease patient: Addressing management conundrum.

Parathyroid carcinoma is a rare malignancy; and it is rarer to find one located in an ectopic location. Ectopic parathyroid glands are a reported cause of failed primary surgery for hyperparathyroidism. We report here a 73-year-old male who previously had parathyroidectomy for primary hyperparathyroidism but then had recurrence of his symptoms with a diagnosis of a mediastinal parathyroid carcinoma on further evaluation. This presentation of complicated mediastinal parathyroid carcinoma posed significant diagnostic and management challenges due to comorbid stage IV chronic kidney disease (CKD). Secondly, due to the same comorbid condition, a more aggressive calcimimetic regimen could not be undertaken due to the risk of renal dysfunction with potential progression to dialysis status. Thirdly, he was a high-risk surgical candidate due to significant cardiovascular risks. Ideally, open surgical intervention would be recommended but due to the associated risks, he was managed with robotic-assisted thoracoscopic surgery. He subsequently developed hypocalcemia which normalized with supplemental calcium at follow-up.

A Surgical Management of Mediastinal Parathyroid Adenoma: A Regional Experience in Malaysia.

Primary hyperparathyroidism (PHPT) usually presents with symptoms of hypercalcemia which is due to excessive secretion of parathyroid hormone (PTH). Surgical removal of the secreting tumor either adenoma or hyperplasia remains the mainstay of treatment. Around 2% to 25% of the lesions are located in the mediastinum. We reviewed our institution's surgical treatment and approach to mediastinal parathyroid adenoma (MPA). We retrospectively reviewed the demography, comorbidities, clinical presentation, surgical approach, and outcome for patients in our institution who underwent surgery for MPA from September 2019 until August 2023. All patients with MPA who underwent surgery were included in the review. The surgical approaches used were both video-assisted thoracoscopic surgery (VATS) and median sternotomy. There were three patients with PHPT due to MPA who underwent surgery. Out of the three patients, two were female. The mean age was 48.6 years old, ranging from 16 to 66 years old. All of them presented with PHPT with a raised mean serum calcium level of 3.52 mmol/L (range: 2.84-4.38 mmol/L) and a mean PTH or intact PTH (iPTH) level of 274.6 pmol/L (range: 8.87-695 pmol/L). Ultrasound of the neck was performed for all the patients before further investigations were done to look for the ectopic parathyroid gland. Computed tomography (CT) of the thorax showed mediastinal parathyroid mass in all the patients with an average size of 2.4 x 2.1 x 2.3cm (range: 1.3-3.8cm), which showed uptake in 99mTc-hexakis-2-methoxyisobuthylisonitrile (Tc99m-MIBI) scintigraphy. VATS was performed for two cases and an upper partial sternotomy was performed for one patient. Postoperatively, iPTH and serum calcium levels were reduced significantly for all patients. There were no post-operative complications in our study. Comprehensive diagnostic imaging and surgical planning are important for the localization of MPA. In our review, all cases were promptly diagnosed and underwent surgery without complication.

Preoperative localization of water clear cell giant parathyroid adenoma: A case report.

Primary hyperparathyroidism commonly results from a solitary parathyroid adenoma. A water clear cell parathyroid adenoma represents a rare histological variant. This report presents the challenges of preoperative detection of a giant parathyroid adenoma, which was of the water clear cell variant. A case of severe hypercalcemia in a patient without clinical symptoms and equivocal findings on standard imaging modalities, in which the use of [11C]C-Methionine PET/CT facilitated the preoperative detection of a giant parathyroid adenoma. Histopathological examination confirmed the diagnosis of a water clear cell giant parathyroid adenoma following surgical excision. These findings highlight the significance of advanced imaging techniques in the detection and management of a rare form of parathyroid adenoma.

A Novel Adult Case of Recurrent Acute Pancreatitis Caused by Hypercalcemia With Concurrent Manifestation of Posterior Reversible Encephalopathy Syndrome Revealing Undiagnosed Primary Hyperparathyroidism due to an Underlying Parathyroid Adenoma.

Background: Hypercalcemia-induced posterior reversible encephalopathy syndrome (PRES) is a rare entity primarily associated with iatrogenic vitamin D/calcium overdose, malignancy, or, infrequently, primary hyperparathyroidism. Case Report: We present a novel case of an adult male from rural India who experienced recurrent acute pancreatitis caused by hypercalcemia with concurrent manifestation of PRES. Diagnostic evaluation revealed markedly elevated serum calcium levels and parathyroid hormone concentrations, consistent with primary hyperparathyroidism. Imaging studies identified a parathyroid adenoma near the right thyroid lobe, subsequently surgically excised. Discussion: This case underscores the importance of considering primary hyperparathyroidism as an underlying cause of PRES, especially in the absence of acute arterial hypertension or autonomic dysfunction. Early recognition and intervention are essential in mitigating the morbidity and mortality of PRES.

Primary Hyperparathyroidism due to Parathyroid Adenoma in Children and Adolescents.

OBJECTIVE: In contrast to adults, primary hyperparathyroidism (PHPT) in children and adolescents is a rare endocrine disorder. METHODS: A retrospective review of PHPT cases between 2005 and 2022 from a single tertiary university medical center, including clinical signs and symptoms, laboratory findings, radiological evaluation, treatment, and postoperative complications. RESULTS: Ten children (mean age at diagnosis 16.3 ± 1.3 years) were diagnosed with PHPT. All patients were in late pubertal stages without sex predominance and 8 were symptomatic. Mean calcium level was 13.6 ± 2.5 mg/dL, and mean parathyroid hormone levels were 204.8 ± 163.1 pg/mL. Parathyroid adenoma was confirmed by the postsurgical pathology results. CONCLUSIONS: PHPT in children and adolescents is often symptomatic and more severe than adults. The main cause is single parathyroid adenoma. Associated hypercalcemic syndromes were not found. Patients were cured after surgical removal of the adenoma without significant postoperative complications and no recurrence during 10.4 ± 5.9 years follow-up.

High lymphocyte signature genes expression in parathyroid endocrine cells and its downregulation linked to tumorigenesis.

BACKGROUND: To date, because of the difficulty in obtaining normal parathyroid gland samples in human or in animal models, our understanding of this last-discovered organ remains limited. METHODS: In the present study, we performed a single-cell transcriptome analysis of six normal parathyroid and eight parathyroid adenoma samples using 10 × Genomics platform. FINDINGS: We have provided a detailed expression atlas of parathyroid endocrine cells. Interestingly, we found an exceptional high expression levels of CD4 and CD226 in parathyroid endocrine cells, which were even higher than those in lymphocytes. This unusual expression of lymphocyte markers in parathyroid endocrine cells was associated with the depletion of CD4 T cells in normal parathyroid glands. Moreover, CD4 and CD226 expression in endocrine cells was significantly decreased in parathyroid adenomas, which was associated with a significant increase in Treg counts. Finally, along the developmental trajectory, we discovered the loss of POMC, ART5, and CES1 expression as the earliest signature of parathyroid hyperplasia. INTERPRETATION: We propose that the loss of CD4 and CD226 expression in parathyroid endocrine cells, coupled with an elevated number of Treg cells, could be linked to the pathogenesis of parathyroid adenoma. Our data also offer valuable information for understanding the noncanonical function of CD4 molecule. FUNDING: This work was supported by the National Key R&D Program of China (2022YFA0806100), National Natural Science Foundation of China (82130025, 82270922, 31970636, 32211530422), Shandong Provincial Natural Science Foundation of China (ZR2020ZD14), Innovation Team of Jinan (2021GXRC048) and the Outstanding University Driven by Talents Program and Academic Promotion Program of Shandong First Medical University (2019LJ007).

Preoperative Lateralization and Diagnostic Value of Selective Bilateral Internal Jugular Venous Sampling in Primary Hyperparathyroidism: Single-Center Experience.

Background and Objectives: Primary hyperparathyroidism (pHPT) is a common endocrine disorder caused by excessive production of parathyroid hormone (PTH) leading to elevated calcium levels. Diagnosis is primarily based on biochemical evaluation, and surgery is the curative treatment. Imaging techniques like ultrasound and Tc-99m Sestamibi scintigraphy are used for localization, but selective Internal Jugular Venous (SVS) becomes valuable in cases of inconclusive or conflicting results. This study evaluated the diagnostic efficacy of SVS for localizing parathyroid adenomas in cases where non-invasive radiological diagnostic methods yielded inconclusive results or negative findings despite clinical symptoms suggestive of pHPT. Materials and Methods: In this retrospective study, a total of 28 patients diagnosed with pHPT underwent SVS at a tertiary center known for receiving referrals from 2017 to 2022. The diagnoses were confirmed through biochemical analysis. The SVS results in 22 patients were compared with non-invasive imaging methods, including ultrasound, scintigraphy, and computed tomography with/without contrast material. SVS was indicated when at least two non-invasive diagnostic procedures failed to clearly localize the parathyroid glands or provided ambiguous results. Results: SVS demonstrated higher sensitivity for localizing parathyroid adenomas compared to non-invasive imaging methods, accurately lateralizing the adenoma in 68.18% of cases. Among the SVS findings, 31.8% of patients had negative results, with 9.1% not having clinically proven parathyroid adenoma, while 22.7% had false negative SVS findings but were later confirmed to have adenoma during surgery. Ultrasound correctly identified the location in 45.45% of cases, CT in 27.27%, and scintigraphy in 40.9%. Conclusions: SVS is a valuable diagnostic tool for accurately localizing parathyroid adenomas in patients with inconclusive non-invasive imaging results. It aids in targeted surgical interventions, contributing to improved management and treatment outcomes in primary hyperparathyroidism.

Intraoperative radio-guided localization of parathyroid adenomas using 3D freehand SPECT technology.

Parathyroidectomy for primary hyperparathyroidism (PHPT) could have poor outcomes, even with accurate preoperative localization of the adenomas, because their intraoperative localization can be challenging. Freehand single photon emission computed tomography (fhSPECT) is a new technique for radio-guided intraoperative navigation. Its use during parathyroidectomy could be useful and such data are limited. We herein present our experience on the feasibility of fhSPECT for intraoperative detection of abnormal parathyroid glands. We retrospectively reviewed the clinical data of 55 patients (30-77 years old) with PHPT due to parathyroid adenomas, that were subjected to parathyroidectomy from 12/2017 to 7/2022. In average, 111 ± 74 MBq of Tc-99 m Sestamibi were injected intravenously, approximately 2 h before the operation and fhSPECT was used to generate 3D images during parathyroidectomy. Measurements of PTH and calcium levels were performed preoperatively, postoperatively and 4-6 months after the procedure. FhSPECT successfully identified the parathyroid adenoma in all the patients. It took 3 min (median time) for fhSPECT to detect at least one radioactive spot in all patients. The mean duration of the operation was 66.6 ± 7.3 min. Forty-nine patients out of 55 had solitary and 6/55 had multiple adenomas, whereas 6/55 had ectopic abnormal parathyroid glands. None of the patients had persistent hyperparathyroidism during follow-up. To the best of our knowledge, this is the largest series of patients with PHPT that underwent fhSPECT assisted parathyroidectomy. Our data suggest that this navigation system is helpful in identifying parathyroid adenomas intraoperatively.

Primary Hyperparathyroidism in Young and Adolescents: Alike or Unlike Adult Hyperparathyroidism? - A Series from South India.

Background: Primary hyperparathyroidism (PHPT) is a common endocrine condition but rare in the pediatric and adolescent populations. The presentations can be unique, accounting for significant morbidity in the case of untimely detection. Aim: To study surgically treated pediatric PHPT retrospectively. Methods: Surgically treated children of PHPT up to 20 years of age between 2010 to 2022 were analyzed. All of them were operated on by an endocrine surgeon and team. Results: There was a total of 712 parathyroidectomies over 12 years, out of which there were 52 children (7.3%) had PHPT at less than 20 years of age. This group included 32 male children. The mean age was 16.1 years, including 7 cases of neonatal severe HPT. Multiple Endocrine Neoplasia type 1 was confirmed in 12 children. Presentations were more severe like bone pain (35.13%), renal stones (27.02%), incidental asymptomatic detection (18.9%), failure to thrive (10.8%), and pancreatitis (8.1%) as compared to adults. Mean serum calcium was 12.9 mg/dl (highest-14.1, N-8.8-10.8 mg/dl), mean parathormone levels were 386.91 pg/ml (N-10-65) and vitamin D levels ranged from 2.9-22.8 ng/ml. Localization was done with ultrasound and 99mTc- SESTAMIBI scans. Mean serum calcium levels in NSPHPT were 28.6 mg/dl (N-8.8-10.8 mg/dl). There were a total of 45 cases (6.32%) of PHPT less than 20 years of age, excluding the cases of NSPHPT. All children underwent parathyroidectomy, with 14 cases having an additional thymectomy, 2 cases with thyroidectomy, and a single case of hemithyroidectomy. The cure rate was 97.3%, while one baby with NSPHPT had persistent disease (postop PTH-110 pg/ml). The uniglandular disease was seen in 54.05% and the rest had a multiglandular disease. Adults accounted for 559/660 cases with 80% uniglandular disease. All cases had a postoperative histopathological confirmation with an average follow-up of 1 year. Conclusion: Childhood PHPT has a few features same as the adult population. Symptomatic presentations like adults, though pancreatitis and fatigue were more commonly seen as compared to bone pain. Calcium, phosphorus, and parathormone levels were comparable. Uniglandular involvement was seen just like the adult population. There are a few others that make them a distinct subtype like their symptoms of bone pain and being more common among boys. One-fourth of them had MEN1. Fewer cases in this age group make them unique.

Predicting tumor volume in primary hyperparathyroidism from preoperative clinical data.

CONTEXT: Primary hyperparathyroidism (PHPT) is an endocrine disorder that is treated surgically, and some correlation between the size of the responsible lesion and preoperative clinical data is assumed. The purpose of this study was to predict tumor volume of the lesion responsible for PHPT from preoperative clinical data. METHODS: Participants comprised patients with surgically treated PHPT who underwent initial surgery in our department between January 2000 and December 2021. The volume of parathyroid gland removed was used as the primary outcome and associations with preoperative clinical data were assessed by multivariable analysis. RESULTS: A positive correlation was identified between parathyroid tumor volume and both preoperative intact parathyroid hormone (PTH) (Spearman's r = 0.503) and calcium values (Spearman's r = 0.338). Data for intact PTH value and tumor volume were logarithmically transformed (ln-PTH = log-transformed intact PTH value; ln-volume = log-transformed tumor volume). Multiple regression analysis revealed male sex, ln-PTH and calcium values as significant predictors of ln-volume, with standardized regression coefficients of 0.213 (95% confidence interval [CI] 0.103-0.323), 0.5018 (95%CI 0.4442-0559) and 0.322 (95%CI 0.0339-0.149), respectively. The adjusted R2 for this model is 0.320. CONCLUSIONS: Preoperative serum intact PTH value is associated with tumor volume of the lesion responsible for PHPT. A rough estimation of the tumor size would provide responsible physicians with opportunities to add further imaging tests or plan appropriate surgical strategies.

Case report: Microwave ablation is a safe and effective method for primary hyperparathyroidism in pregnancy.

Primary hyperparathyroidism (PHPT) is a rare disease in pregnancy and endangers the health of both pregnant women and fetuses. However, the treatments are very limited for PHPT and most of them are unsatisfactory because of the peculiar state in pregnancy. The only curable method is parathyroidectomy which can be safely performed in the second trimester of pregnancy. In this case, we reported a pregnant woman with primary parathyroid adenoma presenting hypercalcemia and severe vomit at the end of first trimester. Finally, she got cured by microwave ablation at the end of first trimester and gave birth to a healthy baby boy.

Testing for Primary Hyperparathyroidism in 17,491 Patients With Hypercalcemia.

BACKGROUND: Primary hyperparathyroidism (PHPT) is underdiagnosed and associated with many adverse health effects. Historically, many hypercalcemic patients have not received parathyroid hormone (PTH) testing; however, underlying reasons are uncertain. Our goals are to determine the PTH testing rate among hypercalcemic individuals at a large academic health system and to assess for characteristics associated with testing versus not testing for PHPT to inform future strategies for closing testing gaps. METHODS: This retrospective study included adult patients with ≥1 elevated serum calcium result between 2018 and 2022. Based on the presence or absence of a serum PTH result, individuals were classified as "screened" versus "unscreened" for PHPT. Demographic and clinical characteristics of these groups were compared. RESULTS: The sample comprised 17,491 patients: 6567 male (37.5%), 10,924 female (62.5%), mean age 59 y. PTH testing was performed in 6096 (34.9%). Characteristics independently associated with the greatest odds of screening were 5+ elevated calcium results (odds ratio [OR] 5.02, P < 0.0001), chronic kidney disease (OR 3.63, P < 0.0001), maximum calcium >12.0 mg/dL (OR 2.48, P < 0.0001), and osteoporosis (OR 2.42, P < 0.0001). Characteristics associated with lowest odds of screening were age <35 y (OR 0.60, P < 0.0001), death during the study period (OR 0.68, P < 0.0001), age ≥85 y (OR 0.70, P = 0.0007), and depression (OR 0.84; P = 0.0081). CONCLUSIONS: Only 35% of hypercalcemic patients received PTH testing. Although the presence of PHPT-associated morbidity was generally associated with increased rates of screening, hypercalcemic patients with depression were 16% less likely to be tested.

Hypercalcemic Crisis Due to a Giant Intrathyroidal Parathyroid Adenoma, with Postsurgical Severe Hypocalcemia and Hungry Bone Syndrome: A Case Report.

BACKGROUND: Parathyroid adenoma is the most common cause of hypercalcemia and rarely leads to a hypercalcemic crisis, which is an unusual endocrine emergency that requires timely surgical excision. CASE PRESENTATION: A 67-year-old male was admitted to the ER of the Euroclinic Hospital, Athens, Greece, because of elevated calcium levels and a palpable right-sided neck mass, which were accompanied by symptoms of nausea, drowsiness, and weakness for six months that increased prior to our evaluation. A gradual creatinine elevation and decreasing mental state were observed as well. The initial laboratory investigation identified severely elevated serum calcium (3.6 mmol/L) levels consistent with a hypercalcemic crisis (HC) and parathyroid hormone PTH (47.6 pmol/L) due to primary hyperparathyroidism. Neck ultrasonography (USG) identified a large, well-shaped cystic mass in the right thyroid lobe. With a serum calcium concentration of 19.5 mg/dL and a PTH of 225.3 pmol/L, the patient underwent partial parathyroidectomy and total thyroidectomy, which decreased serum calcium and PTH to 2.5 mmol/L and 1.93 pmol/L, respectively. Histology revealed a giant intrathyroidal cystic parathyroid adenoma, which was responsible for the hypercalcemic crisis. Postoperatively, the patient developed severe biochemical and clinical hypocalcemia, with calcium concentrations as low as 1.65 mmol/L, consistent with hungry bone syndrome (HBS), which was treated with high doses of intravenous calcium gluconate and oral alfacalcidol, and a slow recovery of serum calcium. After discharge, parathyroid function recovered, and symptomatology resolved entirely in more than one month. DISCUSSION/CONCLUSIONS: We present a case involving an exceptionally large intrathyroidal parathyroid adenoma that is characterized by clinical manifestations that mimic malignancy. The identification and treatment of such tumors is challenging and requires careful preoperative evaluation and postoperative care for the risk of hungry bone syndrome.

Late recurrence of a single gland primary hyperparathyroidism-Atypical parathyroid adenoma or misdiagnosed parathyroid carcinoma.

Key Clinical Message: This case report aims to raise awareness of differential diagnoses of hypercalcemia and primary hyperparathyroidism, including parathyroid carcinoma and atypical adenoma, and to highlight the diagnostic challenges. Abstract: Parathyroid carcinoma is a rare and often fatal cause of primary hyperparathyroidism and hypercalcemia. To date, there is still no clear-cut diagnostic pathway for parathyroid carcinoma established, which results in major diagnostic ambiguity and complexity. Clinical differentiation between benign parathyroid adenoma and carcinoma is challenging and ultimately the diagnosis remains histopathological. We present a case of a 58-year-old female patient with parathyroid tumor recurrence after parathyroidectomy because of primary hyperparathyroidism. The first tumor was histologically classified as an atypical parathyroid adenoma by a specialized endocrine pathologist. Eleven years after the primary tumor resection a new tumor recurred. Retrospectively, after the tumor recurrence, the primary diagnosis of the atypical adenoma was questioned, and the tumor was temporarily classified to rather be a parathyroid carcinoma. This case aims to raise awareness for the diagnostic challenge of parathyroid carcinomas as a rare cause of primary hyperparathyroidism and therewith to improve treatment and prognosis.

Sonographic Features of Atypical and Initially Missed Parathyroid Adenomas: Lessons Learned From a Single-Center Cohort.

CONTEXT: Awareness of typical and atypical ultrasonographic (US) features of parathyroid adenomas (PAs) is crucial since US is the most widely used first-line imaging modality. OBJECTIVE: The purpose of this study was to describe the atypical features of PAs on US and other possible factors leading to a false negative examination in a large single-center cohort. MATERIALS AND METHODS: The US records of 457 PAs in 445 patients with biochemically proven primary hyperparathyroidism (PHPT) were evaluated in a prospectively maintained database. Atypical size, composition, shape, echogenicity, location, and vascular pattern on US were noted. For patients who previously had at least one negative US examination in referring centers, the main possible reason was defined accordingly. RESULTS: The study group included 359 female and 86 male patients with PHPT. Typical sonographic features were observed in 231 PAs (51%), whereas 226 (49%) had at least one atypical US feature. The most common atypical features were atypical size (29%), followed by atypical echogenicity (19%), shape (8%), location (7%), and composition (7%), respectively. There were 122 initially missed PAs in all groups. The most frequent main atypical US features leading to false negative examinations were atypical size (22.1%) and atypical location (18.8%). Inexperience was third most common reason (16.3%) for false negative US examinations. CONCLUSIONS: Almost half of PAs have at least one atypical feature on US. Awareness of the high prevalence of atypical US features could increase the accuracy of US examination and potentially decrease demand for more expensive second-line imaging modalities.