Metastatic parathyroid carcinoma diagnosed after five surgical attempts: a case report and review of the literature.

backgroundDiagnosis of parathyroid carcinoma as a rare cause of primary hyperparathyroidism is usually very challenging, even after surgical resection. CASE PRESENTATION: A 45-year-old woman with a diagnosis of primary hyperparathyroidism underwent surgery three years ago. Parathyroid adenoma resection and total thyroidectomy, due to incidental intraoperative finding of papillary thyroid carcinoma, were performed. She had been asymptomatic for 2.5 years before her PTH and calcium levels rose. The second surgery was performed based on parathyroid hyperplasia diagnosis, but the patient did not recover. She was then referred to us. Imaging modalities could not localize the PTH source. Sequential bilateral neck explorations were unsuccessful. As a last attempt, mediastinal exploration was performed. By confirming no parathyroid tissue in the mediastinum, excision of some tiny pulmonary nodules (previously considered as PTC metastasis) was done, which was confirmed to be parathyroid cancer metastasis.

conclusionsDiagnosing parathyroid carcinoma is difficult because of unreliable diagnostic criteria. The correct diagnosis may be determined through the follow-up for recurrent hyperparathyroidism in a previously diagnosed case of parathyroid adenoma.