Parathyroid Carcinoma: A Report of Two Cases.

Parathyroid carcinoma is a rare cause of hypercalcaemia, which can be potentially difficult to diagnose and treat. Since its clinical, biochemical, and radiological features overlap with those of parathyroid adenoma, diagnosis is often made only after histological review of the resected tissue. We report two cases managed at a United Kingdom district general hospital. The first case was of a 51-year-old man referred with persistent hoarseness and an incidental parathyroid lesion on imaging, in whom progressive hypercalcaemia led to excision and a histological diagnosis of parathyroid carcinoma. The second case was of a 58-year-old woman with recurrent hypercalcaemia after initial parathyroidectomy for presumed adenoma; a second resection and specialist histopathological review established the diagnosis of parathyroid carcinoma. Both patients achieved biochemical remission after definitive surgery, with no evidence of recurrence on subsequent long-term follow-ups. These cases illustrate the diagnostic difficulty posed by parathyroid carcinoma and underscore the importance of considering it in patients with marked or recurrent hypercalcaemia, particularly when associated with very high parathyroid hormone levels or local symptoms such as voice change.