[Development of primary hyperparathyroidism in the follow-up of a patient with Paget's disease].

According to the medical literature, the association of primary hyperparathyroidism and Paget's disease varies from 2.2 to 6%. Up to the year 2006, a total of 73 cases had been described, where both diagnoses occurred simultaneously. However, no manifestation of primary hyperparathyroidism during the follow-up of Paget's disease has been reported in the revised literature. We report the case of a well-controlled patient, who developed primary hyperparathyroidism during the 10-year follow-up of Paget's disease. A 68-year-old male patient with active polyostotic Paget's disease was successfully treated with bisphosphonates for ten years. During follow-up, increased levels of calcemia, ionic calcium, alkaline phosphatase, bone alkaline phosphatase and intact parathyroid hormone values were registered. The patient was diagnosed with primary hyperparathyroidism. As a result of his unstable general health condition, surgery was postponed and intravenous zoledronic acid was prescribed, with a favorable outcome.