bluuebunny/crossref_metadata_2025_split huggingface dataset:
1-25OH2D Mediated Hypercalcemia Secondary to DISR From Immune Checkpoint Inhibitors
Authors: Disanti Domenic , Marr Alissa , Goldner Whitney Sears 
Published: May 2021

Abstract
Background: Drug induced sarcoid like reactions (DISR) have recently been described as a potential consequence of immune checkpoint inhibitor therapy. However, hypercalcemia associated with DISR has not been reported.
Clinical Case: A 72 year old male presented with metastatic melanoma. He initiated therapy with Ipilimumab/Nivolumab (Ipi/Nivo). Three weeks after his first cycle he developed symptomatic hypercalcemia (calcium 14.4 mg/dL), and acute kidney injury (creatinine 3.45mg/dL), PTH 12 pg/mL, 25OHD 51, and PTHrp 0.5. He received IV fluids and IV bisphosphonates and calcium normalized to 9.1 mg/dL and creatinine 1.85 mg/dL. His Ipi/Nivo were stopped due to concern for neurotoxicity. He subsequently switched to Q3week Pembrolizumab (Pembro) and after 2 infusions, he again developed hypercalcemia (calcium 11.8 mg/dL). FDG PET demonstrated a complete radiographic response. Labs showed a 1,25OH2D of 103 pg/mL (reference range 19.9–79.3 pg/mL), PTH of 4 pg/mL and calcium of 11.4 mg/dL. He was treated with prednisone 20 mg QD. After 9 days on prednisone, 1,25OH2D was 26 pg/mL and calcium 9.4 mg/dL. He took prednisone for 3 weeks total. Repeat labs off prednisone for one week were 1,25OH2D of 38 pg/mL and calcium 9.1 mg/dL. He continued on Pembro. After being off steroids for 5 weeks, he developed body aches and swelling of the hands. 1,25OH2D increased to 100 pg/mL and calcium to 10 mg/dL. He restarted prednisone and stopped Pembro. Labs one month later showed a 1,25OH2D of 45 pg/dL while still on prednisone 10 mg qd and a normal calcium in the mid 9’s. Follow up FDG PET showed hypermetabolic bilateral hilar and mediastinal lymphadenopathy not seen on previous imaging. Ultrasound-guided lymph node biopsy revealed granulomatous lymphadenitis. He was diagnosed with DISR, secondary to immunotherapy with checkpoint inhibitors. He continues on prednisone 10 mg per day and calcium and 1,25OH2D levels have remained normal.
Conclusion: This is the first case of 1,25OH2D mediated hypercalcemia as a consequence of DISR induced by immune checkpoint inhibitor therapy. Hypercalcemia in the setting of malignancy is more commonly due to humoral hypercalcemia of malignancy from PTHrp or bone metastasis, but DISR needs to be a consideration in persons with hypercalcemia on immune checkpoint inhibitor therapy, with elevated 1,25OH2D levels and low PTH and PTHrp levels.
A Unique Case of Primary Hyperparathyroidism
Authors: Lucier Jessica , Shakil Jawairia 
Published: May 2021

Abstract
Background: Primary hyperparathyroidism is the most common cause of hypercalcemia. It is more commonly seen in postmenopausal women, but can develop in younger individuals. Brown Tumors are an uncommon finding that can be seen in sever hyperparathyroidism. These bone findings are most often seen in the maxilla or mandible, though can affect any bone. Bone changes are reversible after parathyroidectomy.
Clinical Case: An 18 year old male with a PMH of nephrolithiasis presented with a two day history of flank pain and hematuria. Endocrinology was consulted for hypercalcemia and elevated PTH. He had a family history of nephrolithiasis in his maternal uncle and grandfather, but no known family history of hypercalcemia or thyroid cancer. He was not on any medications or supplements. His initial labs were significant for a calcium of 15.0, PTH of 644, and a Vitamin D 25 of 11.7. He had no known history of hypercalcemia. He was treated with aggressive hydration, 4mg of zometa, 30mg of sensipar and two doses of 200mg calcitonin, with improvement in his calcium levels. Imaging of the abdomen and pelvis revealed multifocal solid-cystic lesions in the right superior pubic ramus and the distal femur, with smaller enhancing lesions in the left subtrochanteric, consistent with Brown Tumors. SpectCT was obtained and significant for a 2.1 by 1.4cm lesion in the anterior superior mediastinum. His overall presentation was consistent with primary hyperparathyroidism secondary to an ectopic parathyroid adenoma. Due to his relative young age at presentation and degree of primary hyperparathyroidism, there was concern for MEN1 or possible parathyroid carcinoma. MRI of the pituitary was obtained and showed a 4mm microadenoma in the right side of the pituitary. Prolactin, thyroid hormones, IGF-1, plasma metanephrines and calcitonin were all within normal limits. CDC73, a genetic marker for parathyroid carcinoma, was negative. Genetic work up for MEN1 was also negative. Endocrine surgery was consulted and he underwent a resection of the ectopic parathyroid adenoma.
Discusion: Though most patients with primary hyperparathyroidism are asymptomatic, nephrolithiasis and Brown Tumors can be seen with more severe cases. It is important to rule out possible genetic causes for primary hyperthyroidism in patients with abnormal presentations, as it will change the overall long term management.
Atypical Parathyroid Adenoma in a Young Man
Authors: Bowen Elizabeth R , Dillon Joseph Stephen 
Published: May 2021

Abstract
Patient is a 38-year-old man who developed sudden onset of pain in the upper left arm while carrying a case of water. The pain recurred periodically over the next few months. He presented to the emergency department where imaging showed a pathologic fracture in the proximal left humerus through a lytic lesion. Laboratory testing showed: calcium 13.8 mg/dL (8.5–10.1 mg/dL), 25-OH vitamin D 8 ng/mL (31–100 ng/mL), parathyroid hormone 1583.1 pg/mL (18.5–88 pg/mL). Neck ultrasound showed a complex nodule in the left neck measuring 4.2 x 1.7 x 2.5 cm. Subsequent biopsy of the left arm lesion showed a Brown tumor. The patient was referred to endocrinology. There was concern for parathyroid carcinoma given the elevated parathyroid hormone and large neck lesion. Technetium-99m sestamibi scan showed a 4.1 x 2.6 x 2.5 cm mass posterior to the left thyroid lobe. He subsequently underwent left hemithyroidectomy and parathyroidectomy. Pathology revealed a 3.1 cm parathyroid mass with scattered fibrous bands, foci of prominent nucleoli and foci of sheet-like trabecular and spindled architecture. It was without necrosis, lymphovascular invasion, perineural invasion, increased mitotic activity, atypical mitoses or invasion into adjacent structures. Thus, it was classified as an atypical parathyroid adenoma.
Primary hyperparathyroidism is the third most common endocrine disorder, but fewer than 2% occur as a result of an atypical parathyroid adenoma. Patients with an atypical parathyroid adenoma tend to have a more dramatic clinical presentation compared to those with classic adenoma. We see higher calcium and parathyroid hormone levels. Atypical parathyroid adenomas are classified as such due to other features which place the lesion at a higher risk for malignant behavior including higher mitotic activity, adherence to adjacent structures, banding fibrosis and a growth pattern that is either solid or trabecular. In contrast to parathyroid carcinoma, atypical parathyroid adenomas do not show invasion into the surrounding tissues or lymphatic/vascular vessels, and there should be no evidence of metastatic disease. The exact definition of an atypical parathyroid adenoma varies among institutions, and recognition of the defining features (or lack thereof) necessitates an experienced endocrine pathologist.
Due to their uncertain malignant potential, patients with an atypical parathyroid adenoma should undergo routine surveillance for recurrence. Routine follow-up of calcium, parathyroid hormone and imaging is indicated to detect for recurrence. A CDC73 germline mutation is associated with recurrence compared to CDC73-negative patients. Parafibromin expression is also thought to play a role although studies so far have had discrepant results.
Atypical Presentation of Familial Hypocalciuric Hypercalcemia: Case Report
Authors: Ali Dalal S , Dandurand Karel , Khan Aliya Aziz 
Published: May 2021

Abstract
Background: Differentiation between familial hypocalciuric hypercalcemia (FHH) and primary hyperparathyroidism (PHPT) can be challenging in certain cases in the absence of DNA analysis of the calcium sensing receptor gene. The distinction between those two clinical entities with overlapping biochemical features therefore relies on the calcium to creatinine clearance ratio (CCCR), which is expected to be low in FHH (&lt;0.01 in 80% of cases and between 0.01 and 0.02 in approximately 20% of patients)1. Patients with PHPT usually have a CCCR of&gt;= 0.02. A lower CCCR between 0.01 and 0.02 can be seen in approximately 20% of patients1,2and is more commonly seen in the presence of vitamin D insufficiency, impaired renal function, low calcium intake or being of African descent. It is advised to stop drugs which can contribute to hypercalcemia and lower the CCCR such as thiazide diuretics prior to evaluating the CCCR.
Clinical Case: A 56-year-old lady was referred for evaluation of persistent hypercalcemia post parathyroidectomy and fatigue. She had mildly elevated ionized serum calcium (iCa) and a mid-normal PTH with a CCCR of 0.024. She had a normal BMD with no prior fragility fractures and passed a kidney stone prior to her presentation. Physical exam was unremarkable. She had previously travelled to Tampa and had a subtotal parathyroidectomy 3 glands (RU, LU, RL) for a possible diagnosis of PHPT, tissue biopsy showed hyperplastic parathyroids. Her MEN1 gene analysis was negative for MEN1 mutation and MRI of the abdomen was unremarkable. Her mother had a diagnosis of PHPT and osteoporosis. The iCa remained mildly elevated at 1.43 mmol/L (1.15–1.3) with a 24 hr urinary CCCR at 0.024 and a mid-normal PTH of 4.4 pmol/L (1.6–6.9). Her eGFR was 104 mls/min, 25 vitamin D 82 nmol/L (75–250), 1,25 dihydroxy vitamin D 122 pmol/L (60–206), PO4 0.90 mmol/L (0.8–1.45) and alkaline phosphatase 46 U/L (35–120) were all normal. She continued to have mild symptoms of hypercalcemia and her bone scan was negative for underlying skeletal pathology.
DNA studies for mutations in the CaSR gene were completed. This confirmed the presence of a heterozygous loss of function mutation in the CASR gene at c493-2A&gt;G which appears to be pathogenic.
Conclusion: The CCCR is useful in differentiating PHPT from FHH however in certain cases of FHH the CCCR may be higher then expected and we have now confirmed the presence of FHH with a molecular diagnosis in a patient with a CCCR as high as 0.02.
References: 1 Gunn, IR, Gaffney, D. Clinical and laboratory features of calcium-sensing receptor disorders: a systematic review. Ann Clin Biochem 2004; 41:441–58 2 Stephen J. Marx, Letter to the Editor: Distinguishing Typical Primary Hyperparathyroidism From Familial Hypocalciuric Hypercalcemia by Using an Index of Urinary Calcium, The Journal of Clinical Endocrinology & Metabolism, 2015
Denosumab Induced Severe Prolonged Hypocalcemia in Metastatic Prostate Cancer
Authors: Mehmood Hassan , Hasan Farhad 
Published: May 2021

Abstract
Background: Denosumab is a RANK-l inhibitor that, in addition to the treatment of osteoporosis, is used in patients with advanced cancer and metastatic bone disease to prevent skeletal-related events. Although denosumab is generally safe and effective, it can cause hypocalcemia which in some patients can be severe and life threatening. We present a case of severe prolonged hypocalcemia after a single dose of denosumab in a patient with metastatic prostate cancer. Case: A 78-year-old male with a past medical history of stage 4 prostate cancer on antiandrogen treatment with GnRH antagonist presented with severe hypocalcemia. Physical exam revealed a blood pressure 125/80 mm Hg, pulse 115 per min and weight 135 lb with negative Chvostek’s and Trousseau’s signs. The electrocardiogram showed supraventricular tachycardia with prolonged QTc interval of 503 ms (&lt;430 ms). Labs showed serum calcium 4.9mg/dL (8.5–10.5), albumin 2.5g/dL (3.6–5.1), corrected calcium 5.7 mg/dL, ionized serum calcium 0.64mmol/L (1.05–1.3), creatinine 1.10mg/dL (0.7–1.2), eGFR &gt;60, phosphorus 2.0mg/dL (2.5–4.5), magnesium 1.9 mg/dL (1.6–2.6), 25-OH vitamin D 29.7 ng/mL (30–100), 1,25 dihydroxy vitamin D 174 pg/mL (18–64), iPTH 244.0 pg/mL (11–68) and PSA 1860 ng/mL. Three weeks prior to presentation, the patient received 120 mg of subcutaneous denosumab. Pre-treatment serum calcium was 9.2 mg/dL (8.5–10.5), and Tc-99m bone scan showed multiple osteoblastic osseous metastatic lesions involving both axial and appendicular skeleton. The patient was diagnosed with denosumab-induced severe hypocalcemia and started on intravenous (IV) calcium gluconate infusion, oral phosphate 250 mg twice daily, and ergocalciferol 50,000 IU twice weekly. He required IV calcium gluconate up to 10 g per day in addition to oral calcium carbonate 2 g t.i.d. for 2 weeks to resolve hypocalcemia and normalize QTc interval. Patient was discharged to nursing home on calcium carbonate 2 g q.i.d. with IV calcium gluconate as needed to keep corrected calcium &gt;8.0 mg/dL. After discharge he required up to 4 g of IV calcium and 8 g of oral calcium per day. Unfortunately, he presented again with severe hypocalcemia 5 weeks after discharge. In addition to current regimen of oral and IV calcium boluses, low dose calcitriol was started. We were only able to maintain his serum calcium&gt;8.0 mg/dL by administering high daily dose of oral calcium carbonate 8 g /day and calcitriol 2 mcg daily. Due to poor prognosis, he was transitioned to hospice care and died 2 weeks later. Discussion: There are not many case reports on severe prolonged hypocalcemia secondary to denosumab in cancer patients but normal kidney function. Our patient remained on high dose of calcium even 101 days after denosumab administration. Reference: 1. Milat F et al. Prolonged hypocalcemia following denosumab therapy in metastatic hormone refractory prostate cancer. Bone. 2013 Aug 1;55(2):305–8.
Ectopic Atypical Parathyroid Adenoma Presenting With Pancreatitis
Authors: Shiu Paul , Tashdjian Caroline , Kaur Tarandeep 
Published: May 2021

Abstract
Background: Atypical Parathyroid Adenoma (APA) and parathyroid carcinomas (PC) are rare parathyroid tumors (&lt;1%) causing primary hyperparathyroidism. We present a case of ectopic APA in the left anterior mediastinum. Case: A 38 year old male with hyperlipidemia admitted for acute pancreatitis noted to have calcium level of 13.4 mg/dl (8.6–10.3mg/dl) in the absence of family history of hypercalcemia or kidney stones. He was treated with zoledronic acid, intravenous fluids and calcitonin for hypercalcemia. Pancreatitis resolved with fluid management. Calcium on discharge was 9.9 mg/dl. 8 week follow-up labs showed PTH of 420 pg/ml (14–64 pg/ml), calcium 10.2 mg/dl, phosphorus 1.9 mg/dl (2.5–4.5 mg/dl), vitamin D 19 ng/ml (30–100 ng/ml), 24-hour urinary calcium 115 mg/24 hour (55–300 mg/24 hour) and calcium to creatinine ratio 0.41. Hence diagnosis of primary hyperparathyroidism was made but given the degree of calcium and PTH elevation there was a concern for PC. Ultrasound of the neck demonstrated no abnormality. Sestamibi scan showed irregular focal accumulation of radiotracer in the left upper mediastinum suggestive of mediastinal ectopic parathyroid adenoma (EPA). CT chest with contrast showed a 3.9 x 2.2 x 3.4cm lobulated, heterogenous, hypodense, minimally enhancing mass in the left anterior prevascular space. Diagnosis of EPA was made and he underwent left video assisted thoracic surgery. Operative findings showed a multilobular mass at the level of the aortic arch between vagus and phrenic nerves. Intraoperative PTH went from 1124 pg/ml pre-incision to 160 at 15-minute post-excision. Postoperative calcium was 9.6 mg/dl and PTH 51 pg/ml. Final pathology showed 3.7 x 2.5 x 2cm, hypercellular parathyroid with prominent fibrous band and parafibromin retention compatible with APA. Discussion: APA is an intermediate form of parathyroid neoplasm with uncertain malignant potential, showing atypical histological features without evidence of invasive growth. This poses a diagnostic challenge of PC as the histopathological features overlap and requires an expert pathologist to make the diagnosis. Inactivating CDC73 mutations, encoding parafibromin, is the most common genetic abnormality. Loss of parafibromin has been seen in 100% cases of PC and predicts poor prognosis. Due to rarity of the disease there are no clear guidelines on follow up. Based on literature, annual follow up is suggested with biochemical testing and imaging for the first 5 years after surgery and every 2–3 years thereafter due to 3% recurrence rate and potential progression to PC. Cetani et al in 2019 reported 672 cases of APA, only 3 were ectopic in the mediastinum thus making our case rare. APA is a rare entity as biochemical profile and histopathological features overlap with PC and can be misdiagnosed. Greater awareness of APA may improve capture of cases, allowing the development of guidelines to recognize and treat it.
Experience With Anti-Sclerostin Antibody for Osteoporosis Patient With End-Stage Renal Disease on Hemodialysis
Authors: Mukaddam Mona Al , Hvisdas Christopher , Sulaj Anisa , Patel Kruti , Tran Richie 
Published: May 2021

Abstract
Background: Romosozumab is a sclerostin inhibitor indicated for treatment of postmenopausal osteoporosis. Sclerostin inhibits Wnt/Beta-catenin signaling pathway. When sclerostin is inhibited, stimulation of this pathway leads to increased bone formation and production of osteoprotegerin, which also decreases bone resorption. Patients with chronic kidney disease (CKD) demonstrate increased levels of sclerostin that negatively correlates with the rate of bone formation; however, data is lacking for use of romosozumab in this patient population. The report herein details the experience of use of romosozumab in a patient with end-stage renal disease (ESRD) on hemodialysis (HD). Clinical Case: A 37-year-old old African American male was referred after multiple rib fractures and severe non-traumatic T8 compression fracture with nerve compression. His past medical history includes lupus nephritis and cerebritis, ESRD on HD since age 22 status post (s/p) failed renal transplant, and tertiary hyperparathyroidism complicated with fracture in iliac brown tumor and mediastinal parathyromatosis s/p three parathyroid surgeries. Bone mineral density by DXA (g/cm2, Z-score) were as follows: lumbar spine (0.700, -4.0) femoral neck (0.676, -3.8), total hip (0.628,-4.0), 1/3 radius(0.443,-6.2). No prior exposure to antiresorptive or osteoanabolic agents. Pertinent labs included serum calcium 8.5 mg/dL (nl 8.9–10.3 mg/dl), albumin 4.2 g/dL, alkaline phosphatase 319 U/L (nl 38–126), Phosphorus 3.1 mg/dL (2.4–4.7), Creatinine 5.62 mg/dl, 25-OH Vitamin D 31 ng/mL (nl 25 - 80), intact parathyroid hormone 17.9 pmol/L (nl 1.6–6.9). Patient was in excruciating pain and not a surgical candidate due to poor bone quality. Osteoanabolic therapy was recommended given the severity of osteoporosis; however, teriparatide and abaloparaitde were contraindicated given comorbidities. The patient was offered off-label use of Romosozumab with clear understanding that the drug is not approved for this indication and safety/efficacy data in ESRD is not known. The boxed warning regarding increased risk of stroke, myocardial infarction and death were discussed and patient was willing to proceed. Repeat DXA after eleven monthly doses of Romosozumab resulted in a remarkable improvement in bone mineral density at all sites: lumbar spine (+47%), femoral neck (+41%), total hip (+28%), 1/3 radius (+20%). Patient tolerated medication with no side effects or fractures. Serum calcium was monitored prior to initiation and before every dose. No doses were held due to abnormal laboratory values or side effects. Conclusion: This case report summarizes successful experience with the use of Romosozumab in one patient with ESRD on HD with favorable outcomes.
Fix That PHEX Loss
Authors: Sunny Sonie Sarah 
Published: May 2021

Abstract
Phosphorous has a critical role in multiple biological functions in the body, such as skeletal mineralization, and an imbalance of this can lead to several musculoskeletal disorders. An important regulator of renal phosphate excretion is fibroblast growth factor 23 (FGF23) which is produced by osteocytes and osteoblasts themselves thus providing a mechanism for the skeletal system to influence its own mineralization needs. PHEX is a gene that regulates FGF23 secretion therefore a loss-of-function mutation in this gene would result in elevated circulating FGF23 and phosphate depletion. This mutation has been identified as a cause for X-linked hypophosphatemia (XLH). Treatment of XLH has been limited and mainly involved phosphorous replacement in combination with 1,25(OH) vitamin D. Antiresorptive osteoporosis treatment can exacerbate the skeletal mineralization process. Here we present a patient with multiple fractures who was on denosumab treatment for presumed osteoporosis before being found to have PHEX mutation. The patient is a 64 year-old female with past medical history of bilateral hip replacement and recurrent femur fractures who was seen in clinic in 2014 due to recurrent fractures and diagnosis of osteoporosis since early 2000s. She had only tried alendronate up until that point. Due to the recurrent fractures she was switched to denosumab therapy while workup was underway for secondary causes. She was found to have low phosphorous levels and elevated FGF23 therefore genetic counseling was pursued and was recommended to check for PHEX mutation. The testing came back positive for loss-of-function mutation in PHEX, and by that point she had received 3 doses of denosumab therapy. She suffered another femoral fracture which was determined to be an atypical fracture, and therefore denosumab treatment was stopped and she was continued on phosphorous replacement as well as 1,25(OH) vitamin D replacement. Most recently her phosphorous levels have been controlled with therapy, and there is current discussion underway to try burosumab, an antibody to FGF23. During evaluation for osteoporosis, it is important to consider phosphorous roles in skeletal mineralization. If recurrent fractures are seen in a patient with low phosphorous levels, especially while they are on conventional antiresorptive osteoporosis medications, genetic testing for PHEX mutations should be considered as well as safely stopping antiresorptive medications.