Intrathymic ectopic parathyroid adenoma caused primary hyperparathyroidism with vitamin D deficiency several years after bariatric surgery.

Up to 25% of patients with primary hyperparathyroidism have ectopic parathyroid adenoma. A 45-year-old formerly obese woman underwent extended thymectomy for a parathyroid adenoma located in hyperplastic thymic tissue, associated with primary hyperparathyroidism and severe vitamin D deficiency, but normal bone mineral density. At nine months follow-up, all laboratory test results were within normal limits and she presented no symptoms and no recurrence of disease. In this case, autonomous growth of a parathyroid adenoma was reasonably secondary to chronic calcium and vitamin D malabsorption, which often occurs after bariatric surgery for pathologic obesity.