Persistent renal hyperparathyroidism caused by intrathyroidal parathyroid glands

Renal hyperparathyroidism usually occurs in chronic renal failure patients on regular dialysis. However, renal hyperparathyroidism resulting from intrathyroidal parathyroid glands is an uncommon condition. We herein present the case of a 35-year-old woman who has been on hemodialysis for 20 years. She had renal hyperparathyroidism with generalized weakness and bone pain for 2 years. The patient initially underwent parathyroidectomy at a local institution, during which two large parathyroid glands were resected from the right side (no parathyroid glands were found on the left side); however, the surgical procedure was unsuccessful, and the patient had persistent renal hyperparathyroidism after the operation. She was then transferred to our hospital and ectopic intrathyroidal parathyroid glands were localized by neck ultrasonography and technetium-99m sestamibi scans with single-photon emission computed tomography imaging preoperatively. A left thyroid lobectomy was performed and two intrathyroidal parathyroid glands were found. The patient recovered uneventfully and her symptoms resolved. Therefore, clinicians should be aware of the possibility of renal hyperparathyroidism resulting from intrathyroidal parathyroid glands in cases where the renal hyperparathyroidism persists after parathyroidectomy.