SAT-058 A Rare Case of Primary Hyperparathyroidism in a Pediatric Patient

Introduction: Primary hyperparathyroidism (PHPT) is the third most common endocrine disorder in adult patients, but it is rare in pediatric patients. It is usually diagnosed when patients present with symptomatic hypercalcemia or known complications. In children, atypical presentation often results in delayed diagnosis and increased morbidity. We report a 10-year-old boy presenting with abdominal pain and emesis, found to have hypercalcemia and, ultimately, PHPT. His genetic evaluation was notable for a mutation in the RET gene (3.2C>A) of unknown clinical significance. Case presentation: A 10-year-old male with a history of constipation presented to the emergency department with five days of abdominal pain and emesis. Initial workup revealed high serum calcium (Ca) of 17.3 mg/dL (8.7-10.7) and ionized Ca (ICal) of 2.01 mmol/L (0.95-1.32). Further evaluations revealed low phosphorus level 3.5 mg/dL (4.5-6.5) and high parathyroid hormone level (iPTH) of 329.2 pg/mL (8.0-85.0). These findings were consistent with PHPT. Neck US demonstrated a cervical mass in the mid-right thyroid measuring 0.5 x0.3 x0.5cm, questionable for parathyroid adenoma, which was confirmed with 99mTc-MIBI scintigraphy and neck CT. His Ca level initially responded to fluid resuscitation and Lasix, with Ca level decreasing to 13.6. However, on hospital day two, his Ca level became refractory to all interventions, rising to 16 and prompting the use of bisphosphonates. The patient underwent neck exploration with partial parathyroidectomy and lymph node excision. Pathology revealed hypercellular parathyroid tissue consistent with parathyroid hyperplasia. Intraoperatively iPTH was reduced from 3,134.7 to 79.8 and remained within normal limits since. Postoperatively course was uncomplicated, and the patient was discharged home on oral Ca carbonate and vitamin D. A genetic evaluation was remarkable for a change in the RET gene (3.2C>A), a finding of unknown clinical significance. This change has not been seen in association with an individual who fulfills the clinical diagnosis of MEN2A. To further determine if the variant identified in the RET gene is a benign variant, the mother was tested for MEN2A and was negative. Father could not be tested, but family history was significant for thyroid malignancies. The patient is currently doing well four months postoperatively. His Ca level remains normal. Due to the genetic finding and the concern of MEN2A syndrome, the patient is followed closely by pediatric endocrinology and genetics. Conclusion: PHPT is a common endocrine disorder in adults but rare in children. The diagnosis of pediatric PHPT is almost always delayed due to atypical presentation and rarity of the disease. As secondary organ damage is common, a multi-organ assessment is mandatory. Due to the association with other syndromes, a genetic evaluation should be performed.