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In patients with chronic renal failure, secondary hyperparathyroidism is a common sequela, ultimately necessitating parathyroidectomy in 38% of patients within 20 years owing to medically refractory hyperparathyroidism.^1- 2 Impaired glomerular filtration leads to decreased circulating 1,25-dihydroxycholecalciferol (calcitriol; active vitamin D), increased serum phosphate, and prolonged half-life of parathyroid hormone.³ Together, these factors lead to hyperparathyroidism and hypocalcemia. Eventually, long-standing hyperparathyroidism can progress to tertiary hyperparathyroidism, a state of autonomous parathyroid function that is not suppressed after renal function is restored, as indicated by hypercalcemia and hyperparathormonemia. This phenomenon results from downregulation of calcium-sensing receptors on the chief cells within the parathyroid glands.⁴ This is most commonly seen in patients with renal failure after undergoing renal transplant.

In recent decades, the percentage of patients with chronic renal failure requiring parathyroidectomy has declined as medical management has improved.⁵ Medical management of secondary hyperparathyroidism includes dietary phosphorus restriction, phosphorus-binding medications, calcitriol, and calcimimetics (cinacalcet). However, secondary hyperparathyroidism sometimes persists despite these interventions. Indications for surgery include failure of medical management, calciphylaxis, parathyroid hormone level greater than 800 pg/mL, hyperphosphatemia, hypercalcemia, hypercalciuria, osteoporosis, and significant symptoms such as pruritus, pathologic bone fracture, and bone pain.⁶ Demeure et al⁷ have argued that patients with secondary hyperparathyroidism are more likely to benefit from parathyroid surgery when they have bone pain, malaise, pruritus, calciphylaxis, or if parathyroid hormone levels are highly elevated (greater than 10 times the reference value). The options for parathyroidectomy in these patients include subtotal (3.5 gland) parathyroidectomy and total (4 gland) parathyroidectomy with autotransplantation. Parathyroid tissue can also be cryopreserved at the time of surgery and autotransplanted later if needed.

The mainstay of treatment for tertiary hyperparathyroidism is surgery.⁷ Because most patients have developed 4-gland hyperplasia, total parathyroidectomy is generally performed, with autotransplantation of 20 to 75 mg of parathyroid tissue.⁸ Autotransplantation is performed in a surgically accessible area, traditionally in the sternocleidomastoid or brachioradialis muscles. The rate of autograft-related recurrent hyperparathyroidism has been estimated at 11.6% in patients with tertiary hyperparathyroidism, even after renal transplantation.⁹

Although notes from this patient's prior operation in his home country were not able to be located, his history suggested a diagnosis of recurrent hyperparathyroidism due to hyperplasia of autotransplanted parathyroid tissue. To confirm this, we performed a fine-needle aspiration biopsy in the clinic, which revealed parathyroid cells.

After discussion with the patient and his nephrologist, excision of the mass was performed using local anesthesia. At the time of surgery, the mass was excised with a cuff of sternocleidomastoid muscle, leaving a small portion of tissue approximately half the size of a normal parathyroid gland in place, pedicled on its blood supply. The postexcision intraoperative parathyroid hormone level was 37.9 pg/mL. Postoperatively, the serum calcium nadir was 7.2 mg/dL, which stabilized with oral calcium supplementation. At the most recent follow-up visit, his calcium level was 8.9 mg/dL and his parathyroid hormone level was 50.5 pg/mL. The final pathologic analysis confirmed hyperplastic parathyroid tissue. The patient will continue to receive close clinical and biochemical surveillance for the possibility of recurrent hyperparathyroidism.

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