Background: During pregnancy, management of refractory hypercalcemia secondary to a parathyroid adenoma must include prompt localization and excision of the mass, irrespective of gestational age.
Case: An 18-year-old woman at 23 weeks of gestation was found to have severe hypercalcemia secondary to primary hyperparathyroidism. She required aggressive intravenous hydration with the addition of furosemide to enhance calcium elimination. After localization of an ectopic adenoma in the mediastinum using nuclear medicine scanning, she underwent a video-assisted thoracoscopic resection of the mediastinal parathyroid adenoma. The patient subsequently had an uneventful delivery at term.
Conclusion: Physiologic changes during pregnancy may delay the diagnosis of severe hypercalcemia secondary to parathyroid adenomas. When conservative management fails, localization and surgical excision of the adenoma become imperative to achieve the best maternal and perinatal outcomes.