Incidence and prognosis of parathyroid gland carcinoma: A population-based study in The Netherlands estimating the preoperative diagnosis

BackgroundParathyroid carcinoma is a rare malignancy and generally is diagnosed after surgery for primary hyperparathyroidism. Lack of a preoperative diagnosis and ill-considered surgical planning with its impact on survival are ill-described.MethodsIn a retrospective population-based cohort study the clinical features, treatment, recurrences, and survival of 41 parathyroid cancer patients are reported and compared with characteristics of patients with primary hyperparathyroidism.ResultsPatients with parathyroid carcinoma had significantly higher serum parathyroid hormone and calcium levels compared with patients with primary hyperparathyroidism. Nineteen patients (46%) had a palpable neck mass. A parathyroid hormone level more than 3 times the upper normal limits was suspicious and levels more than 10 times carried a positive predictive value of 84% for carcinoma. Ten-year recurrence-free and disease-specific survival rates were 71% and 79%, respectively.ConclusionsParathyroid hormone levels of more than 3 times upper normal limits, palpable neck mass, and profound hypercalcemia are suspicious signs of carcinoma necessitating surgical exploration by an experienced surgeon.