A Case of Primary Hyperparathyroidism Secondary to Parathyroid Adenoma in a Pediatric Patient

Although common in adults, primary hyperparathyroidism (PHPT) is a rare condition in children with the most common etiology being solitary parathyroid adenoma (PTA). The typical presentation is symptomatic hypercalcemia. Management of PHTP secondary to PTA requires excision of the adenoma.

A 13-year-old adolescent boy presented because of orbital cellulitis and was noted to have hypercalcemia. Despite this, the patient was curiously asymptomatic. Further investigations yielded an elevated parathyroid hormone (PTH) level and a normal urine calcium-to-creatinine ratio making the most likely cause of hypercalcemia PHTP secondary to PTA. Imaging demonstrated PTA. The patient underwent parathyroidectomy with the pathology demonstrating PTA. Postoperatively, the PTH levels were undetectable; hence, the patient was treated with calcitriol and calcium supplementation for 1 month and 4 months, respectively. Genetic work-up for multiple endocrine neoplasia 1 and rearranged during transfection mutations was negative.

Solitary PTA is the most common cause of PHPT. Adenomas are mostly sporadic or may be a manifestation of an inheritable syndrome, such as multiple endocrine neoplasia. Although symptomatic disease is more common in children, our patient denied any hypercalcemia symptoms. The distinguishing biochemical feature of PHPT because of PTA is high or inappropriately normal PTH level in the context of high-normal or elevated serum calcium levels. Urinary calcium excretion is usually normal or high. PTAs are localized by ultrasound and Tc-99m-Sestamibi scintigraphy. Management includes parathyroidectomy and monitoring for postoperative hypocalcemia.

In a child or adolescent presenting with hypercalcemia and elevated PTH levels, it is important to consider PHPT secondary to PTA, because an early diagnosis will aid in preventing complications from hypercalcemia.