Objective:
Primary hyperparathyroidism secondary to an ectopic parathyroid adenoma is rare among children and adolescents.
Methods:
We describe the case of an 11-year-old girl with incidentally diagnosed primary hyperparathyroidism secondary to an intrathymic parathyroid adenoma and performed a review of the related literature.
Results:

99mTechnetium sestamibi single-photon emission computerized tomography/computed tomography and 4-dimensional computed tomography confirmed the ectopic location of the adenoma. The patient underwent thoracoscopic thymectomy and remained normocalcemic with elevated parathyroid hormone showing a downward trend. Parathyroid hormone normalized 18 months after successful parathyroidectomy.
Conclusion:
We review the case of a rare mediastinal parathyroid adenoma in a pediatric patient and summarize the epidemiologic profile, diagnosis, and management of similar pediatric cases.