Renal hyperparathyroidism is a common complication in patients with chronic kidney disease. Cinacalcet, a kind of calcimimetic, has been reported to be an effective and safe treatment option in renal transplant patients with hyperparathyroidism. However, some patients require parathyroidectomy due to resistance to cinacalcet treatment. It is uncertain when we should give up treatment with cinacalcet and perform parathyroidectomy for persistent hyperparathyroidism.
We experience the first documented case in which cinacalcet-resistant hypercalcemia was caused by a mediastinal hyperplastic parathyroid gland after renal transplantation. The patient received total parathyroidectomy with autograft 4 years before renal transplantation. The levels of serum calcium and parathyroid hormone were controlled well with 25 mg daily of cinacalcet. Despite continuous treatment with cinacalcet, the patient developed hypercalcemia, hypercalciuria and nephrocarcinosis after renal transplantation. A mediastinal parathyroid lesion was revealed by imaging. Eventually, parathyroidectomy was performed for the mediastinal gland for the purpose of preventing new stone formation in the renal graft.
It was suggested that prompt parathyroidectomy is preferable rather than prolonged medical treatment for hypercalcemia resistant to cinacalcet caused by persistent hyperparathyroidism after renal transplantation. Furthermore, we should be extremely careful about hypercalcinuria and nephrocalcinosis when we prescribe cinacalcet for patients under hypercalcemia.