Primary hyperparathyroidism associated with genu valgum in a young girl: Report of a rare case

Primary hyperparathyroidism (PHPT) is rare in children and may present with skeletal deformities. The present case report describes the case of a 12-year-old girl with progressive bilateral genu valgum and bone pain unresponsive to corrective osteotomy and supplementation. She had a prior episode of hypercalcemia during acute pancreatitis. Laboratory analyses revealed elevated calcium levels (12.2 mg/dl), markedly high levels of parathyroid hormone (PTH; 1,574 pg/ml), low vitamin D levels (13.3 ng/ml) and increased levels of alkaline phosphatase (2616 U/l). A neck ultrasonography revealed a right parathyroid adenoma, and radiographs revealed multiple expansile, cystic lesions with a 'soap-bubble' appearance. A histopathological analysis confirmed osteitis fibrosa cystica (brown tumor). Radiofrequency ablation of the adenoma normalized the calcium and PTH levels, with the near-complete radiological resolution of lesions and the marked clinical improvement of genu valgum. The present case report highlights a rare pediatric presentation of PHPT with osteitis fibrosa cystica and genu valgum, initially misdiagnosed as an orthopedic disorder. Early endocrine evaluation in children with unexplained bone deformities is essential to prevent unnecessary surgical interventions and morbidity. Successful management of the parathyroid lesion led to substantial, although not formally quantified, clinical and radiological improvement.