Objective:To analyse and explore the situation and causes of misdiagnosed primary hyperparathyroidism (PHPT), so as to develop some strategies for preventing and reducing misdiagnosis.
Methods:Clinical data of 94 misdiagnosed patients with PHPT treated in Beijing Jishuitan Hospital from November 1992 to April 2009 were collected and analyzed retrospectively.
Results:All cases were confirmed by operation and pathology. Among the 94 cases, 90 cases were of parathyroid adenoma,and 4 cases of parathyroid carcinoma. The rate of misdiagnosis was 97.9%（94/96）.The length of time of misdiagnosis was 2 months to 20 years; ＜1year: 24.4%, 1-2 years: 29.8%, 2-3 years: 12.8%, ≥3 years: 33.0%. The 94 cases were misdiagnosed as 16 sorts of diseases, mainly including osteoporosis (17.6%), pathologic fracture(15.3%), urinary stones (11.1%), bone tumor (8.3%), bone cyst （7.8%）,and rheumatic or rheumatoid  arthritis（7.4%）.The main causes of misdiagnosis were the complexity of clinical manifestations of primary hyperparathyroidism, and lack of the knowledge of primary hyperparathyroidism by some doctors.
Conclusions: The key of preventing and reducing misdiagnosis of primary hyperparathyroidism is to improve the  knowledge of PHPT in clinical doctors, especially in general surgeons, orthopedists, urologists and physicians. Serum calcium should be conducted as a routine examination, and it should be examined repeatedly in high-risk group. Blood PTH should be examined in patients with hypercalcemia.