Hypercalcemia Research Articles

A Case of Primary Hyperparathyroidism With a Hypercalcemic Crisis Resulting in Distinct Bone Mineral Redistribution

A Case of Primary Hyperparathyroidism With a Hypercalcemic Crisis Resulting in Distinct Bone Mineral Redistribution

8032 Clinical And Laboratory Characteristics Of Patients With Primary Hyperparathyroidism Followed At A Brazilian University Hospital

Abstract Disclosure: G. Koga: None. D. Amorim: None. L.M. dos Santos: None. D. Calixto: None. M. Ohe: None. J.G. Vieira: None. M. Lazaretti-Castro: None. Primary hyperparathyroidism (PHPT) is an endocrine disorder characterized by hypercalcemia due to hyperfunction of parathyroid glands. Its clinical presentation has been changing, becoming mostly asymptomatic. However, there are few data on developing countries.Objective: to describe clinical and biochemical features of primary hyperparathyroidism in a Brazilian population of a tertiary hospital. Methods: 259 individuals with PHPT are followed in a school-hospital in Sao Paulo in the last 2 years and this preliminary analysis included 161 of them. Clinical and laboratorial data were obtained by reviewing medical records. Data are presented as median [min-max] and statistical differences were considered if p<0.05. Results: 133 (82.6%) were women (3.7:1 female:male ratio) with a median age at diagnosis of 63 years [24-88]. There was higher prevalence of Caucasian (62.7%) then among Afro-descendants and Asians/indigenous: 35.4% and 1.9%, respectively. 99 (61.5%) patients were asymptomatic. Symptoms were observed in 38,5% (nephrolithiasis, fractures, bone pain, hypercalcemic crisis). Target organ involvement was evaluated: 48.4% had osteoporosis, and 47.2% kidney stones. At diagnosis, median total calcium (tCa) was 11.2 mg/dL [10.0-19.1], ionized calcium (iCa) 1.48 mmol/L [1.30-2.48], PTH 277.7 pg/mL [51.4-2374.0] and 25OHD 23.5 ng/mL [5.0-54.2]. Symptomatic patients were diagnosed younger (61 [24-83] vs 64 [31-88]; p=0.036), had higher tCa (11.4 [10.2-19.1] vs 11.2 [10-16]; p=0.049) and greater prevalence of 25OHD<20 ng/mL (50.0 vs 30.4%; p=0.03) than asymptomatic. Patients with severe hypercalcemia (>14 mg/dL) were diagnosed younger than those with non-severe hypercalcemia (52 [41-54] vs 63 [24-88] years; p=0.002). Patients with osteoporosis had older age at diagnosis compared to those without (64.0 [42-86] vs 61.5 [24-88]; p=0.018). Histological data were obtained from 94 individuals out of 104 submitted to surgery: 59.6% had single adenoma, 39.3% hyperplasia or multiple adenomas and 1.1% parathyroid carcinoma. Patients with single adenoma had higher levels of tCa and iCa than those with multiglandular disease (median of 11.4 [10.0-19.1] vs 10.9 [10.3-13.4]; p=0.042 and 1.52 [1.32-2.48] vs 1.43 [1.30-1.59]; p=0.02, respectively). Conclusion: Our preliminary data showed that most of the patients were Caucasian women presenting with asymptomatic disease. Compared with other countries, we still have a greater proportion of symptomatic presentations (38.5%) and multiglandular diseases (39.3%) than the reported in literature. Severe forms were diagnosed earlier, in younger patients and with a single adenoma, suggesting that they may have a different disease from the asymptomatic ones. These aspects demonstrate that there may be ethnic and environmental influences interfering with the presentation of this disease. Presentation: 6/2/2024

7588 Coexistent Toxic Nodular Goiter And Primary Hyperparathyroidism (PHPT), A Combo With Diagnostic And Management Implications

Abstract Disclosure: D. Dave: None. A. Bhan: None. S.D. Rao: None. About 17-84% of patients with PHPT have concomitant thyroid disorders, but the prevalence of coexistent hyperthyroidism in PHPT varies 9-14 %. A vast majority had Graves’ disease with only 3 cases of toxic multinodular goiter (MNG) and PHPT reported in the literature as of 2022 ([1]). We present a rare case of coexistent toxic MNG and PHPT. Case Description: A 68y woman presented with recent 23 kg unintended weight loss and palpitations, but no other symptoms. Denied having kidney stones or fractures. On examination she had fine tremors of hands, MNG without exophthalmos. An ultrasound showed multinodular MNG with cystic lesions. A diagnosis of toxic MNG was made. Laboratory results were: TSH (<0.01 uIU/mL), free T4 1,68 ng/dL (normal: 0.61-1.44 ng/ml), high serum Ca (11.0 - 11.4 mg/dl) over 4y, but PTH was unavailable prior to the visit when it was 107 pg/ml and 89 pg/ml after 3 months of antithyroid therapy. Despite clinical and biochemical euthyroidism after 3 months, serum Ca and PTH levels remained high (11.4 mg/dl and 89 pg/ml respectively). Because she had pulmonary embolism a few years ago, we deferred parathyroidectomy until complete remission of hyperthyroidism. Discussion: Hypercalcemia is the biochemical hallmark of PHPT but can occur in 2-10% of patients with hyperthyroidism alone but only 1% of those will have coexistent PHPT. When these two conditions coexist, hypercalcemia is moderate to severe, and an occasional patient may present with hypercalcemic crisis (2). Prior to the availability of PTH assays, it was a challenge to diagnose coexistent PHPT. Hypercalcemia in hyperthyroidism responds to propranolol but not in PHPT, although the response is variable (3). With the availability of sensitive PTH assays, this maneuver is not necessary. In most cases, current PTH assays distinguish hypercalcemia of hyperthyroidism with suppressed PTH from coexistent PHPT in whom PTH level is non-suppressed or elevated. Monitoring serum Ca and PTH levels during therapy of hyperthyroidism would be useful as normalization of serum Ca and PTH has occasionally been reported (4). In our patient, serum Ca and PTH levels remained high with 3-months of methimazole and atenolol. The impact of both conditions on bone and mineral metabolism are profound, with fractures and kidney stones. Since kidney stones are uncommon in hyperthyroidism, presence of kidney stone in a hyperthyroid hypercalcemic patient should alert the possibility of PHPT. Similarly, significant decrease in bone density in such patient also raises the possibility of PHPT. Prompt diagnosis and appropriate treatment of both conditions is necessary to avoid irreversible complications.

6940 Thrombotic Events in Primary Hyperparathyroidism: Association or Coincidence?

Abstract Disclosure: I.A. Guatemala Funes: None. Z. Zavgorodneva: None. Y. EL-Soufi: None. A. Khan: None. T. Zahedi: None. F. Zhang: None. Introduction: The classical manifestations of primary hyperparathyroidism are nephrolithiasis, osteoporosis, and hypercalcemia-related symptoms, such as abdominal pain, constipation, polydipsia, and polyuria. Parathyroid crisis is a rare and life-threatening presentation of primary hyperparathyroidism characterized by calcium levels above 14-15 mg/dl and marked symptoms of hypercalcemia. Here, we describe a rare case of bilateral pulmonary embolism in a patient with severe hypercalcemia secondary to parathyroid adenoma. Case Report The patient is a 70-year-old female with a past medical history of primary hyperparathyroidism, who presented with profound fatigue, shortness of breath, polyuria and constipation. The patient denied any trauma, immobilization, or long-distance travel. On physical exam patient was confused, dehydrated, and nonhypoxic but with increased work of breathing. Initial labs showed severe hypercalcemia with calcium 19.2 mg/dL, significant elevated PTH 1113.9 pg/mL from her baseline PTH 380.8 pg/mL, normal 25 VitD, and acute kidney injury with creatinine increased from 0.9 mg/dL to 2.8 mg/dL. The calcium level in 24-hour urine collection was 323 mg/24 hours. CT chest angiogram revealed a bilateral lower lobe pulmonary embolism. The lower extremity duplex was negative for venous thrombosis. Thyroid ultrasound demonstrated suspected left parathyroid adenoma 2.1 x 2.1 x 1.4 cm. Renal ultrasound was negative for renal calculi. Following treatment with intravenous fluids, Calcitonin, and Denosumab, her calcium level improved to 10.1 mg/dL. The patient’s symptoms improved and underwent parathyroidectomy. PTH levels decreased significantly after parathyroidectomy. Pathology report confirmed parathyroid adenoma. Discussion The association between hypercalcemia and venous or arterial thrombosis has been rarely reported. Calcium participates directly in the platelet activation, platelet aggregation, and coagulation cascade. However, the true correlation between hypercalcemia and thrombosis is not well understood. It is believed that indirect factors such as vasoconstriction, dehydration, and cytotoxic effects due to hypercalcemia and the direct effects over platelet function and coagulation, may act together to induce thrombosis. Unfortunately, much of the evidence between hypercalcemia and hypercoagulability is based on case reports and our case could be one more evidence that this correlation exists. The patient’s age, absence of other risk factors of hypercoagulability, simultaneous manifestation of hypercalcemic crisis, and acute PE make hypercalcemia as a more likely pathogenetic origin of thrombus formation. Conclusion: Physicians should be cautious of the hypercalcemia-induced thrombotic events caused by dehydration and calcium-triggered vasoconstriction, clotting system activation, or platelet aggregation. Presentation: 6/3/2024

A case with respiratory failure caused from iatrogenic hypercalcemic crisis

Hypercalcemia is a critical and urgent clinical condition that can lead to death, related to blood calcium levels. We present a case of a 69-year-old female who presented with respiratory and renal failure, depression due to iatrogenic hypercalcemia developing in a patient using uncontrolled calcium and vitamin D.

Parathyroid carcinoma located in the thyroid gland: A case report

BACKGROUND Parathyroid carcinoma (PC) is a difficult-to-diagnose rare disease with low incidence. Relatively accurate preoperative diagnosis is very important in choosing surgical methods and patient prognosis. CASE SUMMARY This study reported the clinical diagnosis and treatment of a rare patient with PC located in the thyroid gland and provided a case reference for the diagnosis and treatment of PC. A case of a 64-year-old male patient who presented to our hospital with systemic muscle and joint pain and palpitations is outlined. Subsequently, the patient was admitted to the Department of Nephrology for the treatment of “multiple myeloma nephropathy pending investigation”. The patient was diagnosed with “primary hyperparathyroidism and hypercalcemic crisis” using thyroid color ultrasound. CONCLUSION The intraoperative frozen section report considered the parathyroid tumor. Surgical tumor resection was promptly performed, and the diagnosis of PC was confirmed.

Medication reconciliation to minimise medication errors: Iatrogenic hypercalcaemia as a case report

Hypercalcaemia is a relatively less common yet life-threatening electrolyte disorder and is caused by parathyroid-dependent and independent factors. This case report describes an elderly lady, a known patient of stable hypothyroidism, hypertension, type 2 diabetes mellitus and non-oliguric chronic kidney disease-IV who presented with complaints of gradually worsening drowsiness. Investigations revealed a hypercalcemic crisis; all other contributory investigations were unremarkable. She was put on intravenous saline rehydration, furosemide, pamidronate, and calcitonin. However, due to new-onset haemodynamic instability, cardiomyopathy, and worsening renal parameters, haemodialysis was initiated to reduce the serum calcium levels rapidly. The patient remained asymptomatic after that, and her renal parameters improved to near baseline levels, though cardiac function improvement was not obtained at the end of one month. History elicited from the patient after her neurological improvement revealed that failing to interpret the prescription of three orthopaedics she had visited lately, she followed all simultaneously and had thus consumed toxic levels of calcium and Vitamin D. Medication reconciliatory measures such as e-prescribing, computerised drug dispensing system, automated patient drug dispensing boxes and ‘brown-bagging’ all ongoing medications during the physician visits would ensure reduction in medication errors, thus avoiding adverse events, reducing uncalled for mortalities and morbidities and healthcare cost.

Hypercalcaemic Crisis Associated with Hyperthyroidism: A Rare and Challenging Presentation

A 51-year-old female with a history of multinodular goitre presented with vomiting, abdominal discomfort, and generalized tiredness. Investigations revealed hypercalcemia (ionized calcium 1.41 mmol/L), hypokalaemia, suppressed parathyroid hormone, and significantly elevated free thyroxine (> 7.77 ng/dL) with a suppressed thyroid-stimulating hormone level consistent with hyperthyroidism. Further, the workup confirmed Graves’ disease as the underlying aetiology. Hyperthyroidism is occasionally associated with mild to moderate hypercalcemia, but severe hypercalcemia or hypercalcaemic crisis is an extremely rare complication. Prompt recognition and treatment are crucial to prevent life-threatening complications. The patient was treated with intravenous fluids, a low-calcium diet, zoledronic acid, carbimazole, and a beta-blocker, leading to improvement in her condition. This case highlights a rare occurrence of hypercalcaemic crisis in a patient with thyrotoxicosis due to Graves’ disease. Hyperthyroidism-induced hypercalcemia requires prompt recognition and multidisciplinary management involving endocrinologists, internists, and critical care specialists to prevent potentially life-threatening complications. Healthcare providers should consider the hypercalcaemic crisis in the differential diagnosis of hypercalcemia in the context of hyperthyroidism.

Hypercalcemic crisis in pregnancy, a case report

Hypercalcemic crisis in pregnancy, a case report

Primary hyperparathyroidism revealed by hypercalcemia crisis

Primary hyperparathyroidism revealed by hypercalcemia crisis

Hypercalcemic Crisis Due to Parathyroid Adenoma Improved by Continuous Hemodialysis with a Common Calcium Concentration Dialysate: Discussion of Therapeutic Management.

A hypercalcemic crisis due to primary hyperparathyroidism is a life-threatening condition. We herein report a 71-years-old man with hypercalcemic crisis due to primary hyperparathyroidism with parathyroid adenoma. Generally, hemodialysis or continuous hemodiafiltration using calcium-free or low-calcium dialysate is performed early for hypercalcemic crisis. In this case, continuous hemodialysis with a common calcium concentration dialysate improved the hypercalcemic crisis, and parathyroidectomy was performed. The patient recovered sufficiently. Prediction of hypercalcemia crisis, appropriate introduction and methods of blood purification therapy, and timing decisions for parathyroidectomy are required for therapeutic management of hypercalcemic crisis with parathyroid adenoma.

94 A medical emergency: Hypercalcemic crisis due to vitamin D misuse requiring hemodialysis

94 A medical emergency: Hypercalcemic crisis due to vitamin D misuse requiring hemodialysis

Safety and Efficacy of Denosumab in Children With Osteogenesis Imperfecta-the First Prospective Comparative Study.

Denosumab is a potential therapeutic agent for osteogenesis imperfecta (OI), but its efficacy and safety remain unclear in children with OI. We aimed to investigate the effects of denosumab on bone mineral density (BMD), spinal morphometry, and safety in children with OI compared with zoledronic acid. In this prospective study, 84 children or adolescents with OI were randomized to receive denosumab subcutaneous injection every 6 months or zoledronic acid intravenous infusion once. Changes of BMD and its Z-score, vertebral shape, serum levels of calcium and bone turnover biomarkers were assessed during the 1-year treatment. After 12 months of treatment, BMD at the lumbar spine, femoral neck, and total hip significantly increased by 29.3%, 27.8%, and 30.2% in the denosumab group, and by 32.2%, 47.1%, and 41.1% in the zoledronic acid group (all P < .001 vs baseline). Vertebral height and projection area significantly increased after denosumab and zoledronic acid treatment. Rebound hypercalcemia was found to be a common and serious side effect of denosumab, of which 14.3% reached hypercalcemic crisis. Rebound hypercalcemia could be alleviated by switching to zoledronic acid treatment. Treatment with denosumab or zoledronic acid is beneficial in increasing BMD and improving the spinal morphometry of children with OI. However, denosumab should be used with caution in pediatric patients with OI because of its common and dangerous side effect of rebound hypercalcemia. The appropriate dosage and dosing interval of denosumab need to be further explored in children with OI.

Clinical Characteristics and Management of Hypercalcemic Crisis in 155 Patients: A Single Center Retrospective Study.

This study aimed to analyse the etiology and clinical characteristics of hypercalcemic crisis in a large cohort of Chinese patients and summarised our clinical experience in the management of this serious endocrinological emergency. This was a retrospective analysis of a cohort of patients with hypercalcemic crisis hospitalized in the First Medical Center of Chinese PLA General Hospital between January 2009 and March 2024. The general data, clinical manifestations, etiology, photographic examination, emergency treatment, etiological treatment, and prognosis were analysed. A total of 155 patients with hypercalcemic crisis (91 males and 64 females) with a mean age of 54.60 ± 16.99 years old were enrolled. The most frequent disease-causing hypercalcemic crisis was hyperparathyroidism (41.94%), followed by solid malignancy (41.29%) and multiple myeloma (9.03%), et al. Patients mainly presented with symptoms of the digestive system (78.10%), nervous system (63.30%), skeletal system (59.60%), urinary system (59.50%), and cardiovascular system (34.90%). These 155 patients with hypercalcemic crisis got effective therapies that included simultaneous administration of intravenous injection (IV) isotonic saline, subcutaneous calcitonin, bisphosphonate, or hemodialysis in serious cases. After emergency treatment, all the symptoms in the patients were relieved obviously. The cure rate of hypercalcemic with etiological treatments was 84.50% (131/155). Hypercalcemic crisis is a serious endocrinological emergency with a variety of etiologies and a high risk of mortality. A prompt diagnosis and the implementation of a comprehensive and effective treatment can efficiently alleviate this endocrinological emergency. Etiological treatment targeting different causes can improve prognosis significantly.

Two cases of parathyroid tumor with hypercalcemic crisis

Two cases of parathyroid tumor with hypercalcemic crisis

Urinary tract infection triggering hypercalcemic crisis in an asymptomatic patient with primary hyperparathyroidism

Hypercalcemic crisis (HC) is a rare and severe complication of primary hyperparathyroidism (PHPT), characterized by markedly elevated serum calcium levels and diverse clinical manifestations. PHPT is the primary cause of hypercalcemia and is often asymptomatic. The factors that trigger HC in PHPT are not fully understood. Here we report a patient who was diagnosed with HC resulting from previously undetected PHPT. Remarkably, the patient exhibited no symptoms of PHPT before the HC episode. The patient presented with neurological symptoms, including altered behavior and slurred speech, which were attributed to hypercalcemia. The probable trigger for HC in this case appears to be an acute febrile illness related to a urinary tract infection (UTI). The occurrence of an acute febrile illness or UTI as a precipitating factor for HC in PHPT is a rare and infrequently documented phenomenon in the existing medical literature.

Hypercalcemic crisis: clinical picture and perioperative management

.

SAT207 Parathyroid Carcinoma: A Case Report

Abstract Disclosure: K.T. Sy: None. Background: Parathyroid carcinoma is a rare malignancy, accounting for less than 1% of causes of primary hyperparathyroidism. Case reports have mentioned of parathyroid carcinoma arising in patients with prior neck irradiation, in secondary and tertiary hyperparathyroidism and in patients with history of thyroid cancer and parathyroid adenoma. However, none of these reported associations have been completely established. Clinical Case: The is a case of a 59-year old male presenting with hypercalcemia. He was diagnosed with primary hyperparathyroidism secondary to a parathyroid adenoma, underwent parathyroidectomy with resolution of the hypercalcemia. Six years later, patient had recurrence of hypercalcemia with elevated PTH levels. Parathyroid imaging revealed a mild sestamibi-avid focus in the left retrosternal region, suggestive of an ectopic parathyroid gland and radio-guided neck exploration was done with excision of lesion. Histopathological report revealed parathyroid carcinoma. Two years later, there was recurrence of parathyroid carcinoma but mediastinal exploration revealed no lesions consistent with parathyroid carcinoma. Hypercalcemia with hyperparathyroidism persisted, and cinacalet was started but the patient could not tolerate the nausea associated with the medication. Repeat parathyroid imaging revealed sestamibi-avid lesions in the right retroclavicular, left prevascular/retrosternal, and a left paratracheal areas. Surgical exploration was offered but the patient refused. The patient also developed hypertension and low bone density was noted on dual X-ray absorptiometry (DXA) scan. He was started on denosumab 60 mg subcutaneously every 6 months, which was increased to 60mg every month and then 120mg every month to maintain normal calcium levels. The patient also developed chronic kidney disease, eventually requiring hemodialysis for elevated creatinine levels and hypercalcemic crisis. Soon after hemodialysis was started, the patient had a myocardial infarction and eventually expired. Conclusion: Complete surgical resection is the primary mode of therapy in parathyroid carcinoma, although hypercalcemia is the main cause of morbidity and mortality, rather than the tumor burden. The adjuvant use of radiotherapy and chemotherapy are still controversial. Some studies have shown that long term survival is favorable, but recurrences are frequent and patients tend to live a life filled with long-term follow up, multiple laboratory exams and imaging, hospitalizations and frequent reoperations. Mortality is usually due to uncontrollable hypercalcemia, leading to renal failure and cardiac arrhythmias. Presentation: Saturday, June 17, 2023

SAT205 99Technitiumm Sestamibi Negative Sporadic Metastatic Parathyroid Carcinoma In A Young Female-A Diagnostic Conundrum

Abstract Disclosure: D.V. Reddy: None. S. Paidipally: None. V. kyatham: None. S. Palle: None. C. Bhandiwad: None. Background: Parathyroid carcinoma (PC) is a very rare and indolent endocrine malignancy occurring a decade earlier than parathyroid adenoma. It can present as recurrent pancreatitis, anemia, and peptic ulcers. Serum calcium &amp;gt;14mg/dl, 3-10 times ULN of PTH, and concomitant renal and bone involvement should arise suspicion for PC. PC is diagnosed only through histopathology in the majority. It can also present during a prolonged follow-up, either by local recurrences or distant metastases. Clinical Case: A 27 year old female presented with hypercalcemic crises (as pancreatitis). At admission serum calcium and PTH were grossly elevated; 15.1 mg/dl (8.5-10 mg/dl) and 363 pg/ml (10-55 pg/ml) respectively. Abdominal CT revealed acute pancreatitis with medullary nephrocalcinosis. Ultrasonography of the neck revealed a colloid cyst in the right lobe of thyroid.99Tc m-sestamibi /SPECT-CT revealed no uptake. CT neck and chest showed a 13 mm X 13 mm well-defined round nodular lesion in the left apico-posterior segments of the lung. 18F-FDG PET/CT revealed uptake in the lesion with an SUV max of 10, suggestive of a metabolically active solitary pulmonary nodule. She had a similar presentation 8 years back and was diagnosed to have parathyroid adenoma for which she underwent resection. Serum PTH and calcium levels normalized postoperatively and also on follow-up till 3 years. Differentials include-recurrent ectopic parathyroid adenoma, parathyromatosis, and metastatic parathyroid carcinoma. After managing hypercalcemia medically, the patient underwent video-assisted thoracoscopic surgery with left lung wedge resection. Postoperatively serum calcium and PTH normalized. Histopathology revealed a grey-white nodule of 1.4X1.5X1.2 cm with sections, showing a well-defined lesion composed of lobules and nests of tumor cells separated by thin-walled vascular sinusoids. Tumor cells were polygonal with well-defined margins, moderate granular cytoplasm, and vesicular nuclei showing prominent nucleoli with a mitotic activity of 9/hpf. Immunohistochemistry revealed staining with PanCK, GATA3, and S100 with focal PAX 8 activity in the periphery. MIB index was 18%.IHC was suggestive of a neuroendocrine tumor consistent with metastatic parathyroid carcinoma. Whole exome sequencing did not reveal any pathogenic variants. Conclusion: Though 99Tc MIBI is useful in localizing PC, there are reports of false negative MIBI in documented cases of PC, which has been ascribed to the defective transport to the interior of the malignant cells. This demonstrates the importance of a multimodality imaging approach in such cases. 99Tc MIBI may miss certain cases of PC substantiating the importance of 18F-FDG PET/CT in diagnosis as well as follow-up. Reference: Evangelista L et al. FDG-PET/CT and parathyroid carcinoma: Review of literature and illustrative case series. World J Clin Oncol 2011; 2(10): 348-354. Presentation: Saturday, June 17, 2023

SAT203 Parathyroid Adenoma Masquerading As Parathyroid Carcinoma

Abstract Disclosure: M. Fariduddin: None. A. Lupieri: None. H.L. Calero: None. A. Rubenfeld: None. Y. Eisenberg: None. Case: 22 y/o pregnant female (5 weeks gestation) presented to the endocrinology clinic after a hospital admission for nausea, vomiting, constipation, fatigue and joint pain with labs showing calcium (corrected) of 14 mg/dL and PTH of 1200 pg/ml. Labs in the clinic showed calcium at 16 mg/dL and PTH 1500 pg/ml. She was re-admitted for IV fluids, calcitonin and zoledronic acid. Severe hypercalcemia, young age, and extremely high PTH levels were highly suggestive of parathyroid cancer. CT of neck showed a 2 cm right inferior parathyroid mass abutting the esophagus with concern for esophageal invasion with no evident plane between the mass and the esophagus. No cervical adenopathy was noted. Patient in conjunction with her obstetrician made an informed decision to terminate the pregnancy as this was an undesired pregnancy. She underwent an urgent right inferior gland parathyroidectomy. The mass was not fixed to underlying structures and was resected in-toto. Pathology showed chief cells with clear cytoplasm, and homogeneously round nuclei. There were no atypical mitoses, lymphovascular invasion, perineural invasion, or other invasive features concluding the final pathology as parathyroid adenoma. Discussion: Primary hyperparathyroidism predominantly affects postmenopausal women. Most common cause is parathyroid adenoma (80-85%). Parathyroid carcinoma is a rare cause of primary hyperparathyroidism (1-2%).80% people with parathyroid adenoma and primary hyperparathyroidism are diagnosed incidentally with mildly elevated calcium. PTH elevation is around 1.5-2 times the upper limit of normal. Symptoms are mild sequelae of hypercalcemia. PTH levels 5-10 times upper limit of normal, severe hypercalcemia (Ca &amp;gt; 14 mg/dl) or a hypercalcemia crisis are highly suspicious for parathyroid cancer. Surgical resection is the mainstay of treatment. Clinical criteria play a key role in early identification of parathyroid carcinoma in order to get these patients to surgery before tumor spread and improve long term survival. Our patient with significantly elevated calcium and parathyroid hormone had an atypical presentation of a parathyroid adenoma thus uncovering the limitations of clinical criteria in identifying a parathyroid carcinoma. Most of the patients with a parathyroid adenoma will eventually require surgery, however the technique, extent and urgency of surgery is affected based on clinical situations like these. The timing of the surgery could be detrimental when coupled with a scenario like our patient’s pregnancy wherein you could delay the surgery until the second trimester had the patient wanted to continue the pregnancy. This case highlights the importance of awareness of atypical presentations of parathyroid adenomas and to have a cautious approach in patients with clinical concern for parathyroid carcinoma especially if there is a potential benefit to delay surgery. Presentation: Saturday, June 17, 2023