Intrathyroid parathyroid gland and neonatal primary hyperparathyroidism.

Neonatal hyperparathyroidism (NPHP) is exceedingly rare and often fatal. A neonate is presented with a serum calcium concentration of 33 mg/dL, an intrathyroid parathyroid gland, and a family history of hypocalciuric hypercalcemia (FHH). She underwent successful total parathyroidectomy. Six years later, the child is normocalcemic and developmentally normal, requiring calcium and calcitrol replacement. The results of this case support the concept that NPHP is associated with parathyroid hyperplasia and is part of a continuum that includes FHH.