Introduction:
Primary hyperparathyroidism (PHPT) is an unusual childhood disease characterized by an excessive secretion of parathyroid hormone (PTH). Its presentation may consist of nonspecific symptoms. Consequently, physicians have trouble diagnosing the disease as they fail to check the level of calcium or PTH.

Aim:
To describe a case of a paediatric patient with primary hyperparathyroidism, who was successfully diagnosed and treated.

Case study:
A 14-year-old boy was admitted to the Paediatric Department with suspected PHPT after performing tests at the Endocrinology Outpatient Clinic, which revealed hypercalcaemia and high PTH level. The ordering of tests was motivated by non-specific symptoms that could indicate PHPT. The ultrasonography, single photon emission computed tomography of the neck and Tc-99m MIBI parathyroid scintigraphy of the neck and upper thorax were performed, which revealed the presence of hypoechogenic structure and focal accumulation of a marker, consistent with the presence of adenoma. The patient was qualified for surgical treatment, which resulted in a resolution of pathological symptoms.

Results and discussion:
Because PHPT is a rare disease among paediatric patients, and is initially characterised by non-specific clinical picture, it is usually diagnosed when advanced organ changes occur. Screening tests, such as calcium and PTH determinations, are also not routinely ordered in this age group. Once the diagnosis is made, the treatment is largely supportive and includes prevention of life-threatening complications.

Conclusions:
A rare case of a boy with parathyroid adenoma was successfully managed with a multidisciplinary approach combining input from paediatric endocrinologists, radiologists and surgeons.