Metachronous Double Parathyroid Adenomas Involving Two Different Cell Types: Chief Cell and Oxyphil Cell

Abstract

To describe a patient with the rare occurrence of metachronous double parathyroid adenomas involving two different cell types. We present a case report and a summary of the related literature. Double parathyroid adenomas are rare, occurring in 1.7 to 9% of patients with primary hyperparathyroidism. Most double parathyroid adenomas are synchronous lesions; few metachronous double parathyroid adenomas have previously been reported. Most parathyroid adenomas are of the chief cell variety, with oxyphil cell adenomas occurring in less than 1% of cases. In a 73-year-old man with no prior history or known family history of endocrine disease, primary hyperparathyroidism developed, and cervical ultrasonography demonstrated a mass in the right side of the neck. Subsequent parathyroidectomy revealed a right superior chief cell adenoma. Postoperatively, the patient's parathyroid hormone and serum calcium levels returned to normal and remained so for at least 9 years. Twelve years after the first operation, recurrent hyperparathyroidism prompted repeated surgical exploration of the neck, which disclosed a large left superior parathyroid mass. Surgical excision and histologic examination revealed the lesion to be an oxyphil cell adenoma. To our knowledge, this is the first reported case of metachronous double parathyroid adenomas involving two different cell types: chief cell and oxyphil cell.