SPECT/CT in the diagnosis of ectopic parathyroid adenoma (case report)

Case study: a parathyroid tumor ectopic to the mediastinum. The diagnostic capabilities and advantages of the 99mТс-sestamibi SPECT/CT hybrid method in the preoperative localization of abnormally located parathyroma are demonstrated.

Primary Hyperparathyroidism From Ectopic Parathyroid Adenoma in a Patient With Bilateral Slipped Capital Femoral Epiphysis

Background: Primary hyperparathyroidism has been reported in 13 pediatric patients presenting with slipped capital femoral epiphysis (SCFE), but never in patients with ectopic parathyroid adenoma [1]. Case report: A 12-year-old boy with obesity (BMI 99th percentile) and autism spectrum disorder presented with a limp and was found to have bilateral SCFE. Calcium was elevated to 12.3 mg/dL (reference range 8.0–10.5) with phosphorus of 3.2 mg/dL (3.0–5.7), alkaline phosphatase 775 units/L (40–360), tubular reabsorption of phosphorus 89% (&gt 95%), 25OH-vitamin D 12.1 ng/mL (30–80), 1,25OH-vitamin D 246.6 pg/mL (19.9–79.3), and PTH 1191 pg/mL (10–65). He had significant neuropsychiatric agitation but denied constipation, polyuria, and other symptoms of hypercalcemia. He had in situ pinning of the SCFE bilaterally and was hyperhydrated with minimal improvement in his calcium level. Neck ultrasound revealed no parathyroid adenoma. He was discharged on cholecalciferol 1000 IU daily with plans for outpatient Tc-99m Sestamibi scintigraphy. Following discharge, he developed significant nausea, did not tolerate the cholecalciferol, and was non-weight bearing. Repeat labs and imaging 5 days later demonstrated calcium had risen to 16.7 mg/dL with phosphorus of 2.2 mg/dL. He was admitted and calcium improved transiently to less than 12 mg/dL with intranasal calcitonin therapy. Sestamibi and subsequent CT scan revealed a 2.7x1.6x1.9 cm ectopic parathyroid adenoma in the upper anterior mediastinum. He had thoracoscopic resection of the mass, which was revealed to be intrathymic, and PTH levels fell from 1613 pg/mL pre-operatively to 76 pg/mL 30 minutes post-resection. Post-operatively, he developed hungry bone syndrome with a calcium nadir of 7.6 mg/dL and phosphorus nadir of 1.6 mg/dL, which required oral calcium and calcitriol for 10 days. With normalization of his calcium, his neuropsychiatric symptoms improved. Pathology revealed a parathyroid adenoma. Conclusion: Primary hyperparathyroidism can be associated with SCFE and should be considered even in patients with traditional risk factors for SCFE, especially with bilateral disease. Pediatric patients with primary hyperparathyroidism and negative neck imaging should be further evaluated for ectopic parathyroid adenomas. References: 1. George, G.S., Raizada, N., Jabbar, P.K., Chellamma, J., Nair, A. Slipped Capital Femoral Epiphysis in Primary Hyperparathyroidism - Case Report with Literature Review. Indian J Endocrinol Metab. 2019 Jul-Aug;23(4):491–494.

A Unique Case of Primary Hyperparathyroidism

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.