Primary Hyperparathyroidism Masquerading as Rickets

Primary hyperparathyroidism (PHPT) is common among adults. However, its incidence is rare among children associated invariably with delay in diagnosis. In children, it is caused by hyperplasia, adenoma or related hereditary disorders. Herein, a 17-year male with PHPT presented with rare skeletal manifestations of genu valgum and bilateral epiphyseal displacement of femur. Investigations done three years ago reported hypocalcemia and vitamin-D deficiency. He was diagnosed with rickets and received plenty of calcium and vitamin D supplements. Due to lack of clinical improvement following the supplementation, re-evaluation revealed hypercalcemia, elevated vitamin D levels and elevated parathyroid hormone (PTH). A 99mTc-sestamibi scan reported increased uptake in the left inferior lobe of the thyroid gland. Surgical removal of the parathyroid gland was done and histopathology revealed parathyroid adenoma. Rickets in the setting of PHPT can masquerade as PHPT. In a patient with rickets, hypercalcemia at presentation or following the calcium and vitamin supplementations, should warn the physicians to rule out PHPT.