Primary Hyperparathyroidism From Concurrent Parathyroid Hyperplasia and Ectopic Parathyroid Adenoma: A Case Report.

Primary hyperparathyroidism (PHPT), whether caused by an adenoma or hyperplasia, can be curative with parathyroidectomy. However, persistently elevated parathyroid hormone (PTH) despite parathyroidectomy suggests multigland disease. We present a case of concurrent single-gland parathyroid hyperplasia and an ectopic parathyroid adenoma in a 72-year-old woman with long-standing PHPT. Despite persistently elevated calcium and PTH levels, all diagnostic imaging was negative for parathyroid hyperplasia and adenoma. PTH remained elevated despite initial parathyroidectomy for hypercellular tissue consistent with hyperplasia. An ectopic paraesophageal parathyroid adenoma was ultimately discovered and resected, resolving the PHPT. This case emphasizes that negative imaging does not exclude active parathyroid disease.