title: Unusual presentation of primary hyperparathyroidism: report of three cases.
abstract: BACKGROUND
  Primary hyperparathyroidism is an endocrinopathic condition characterized by hypersecretion of parathyroid hormone. Excess parathyroid hormone results in an altered state of osseous metabolism involving bone resorption and tissue change known as osteitis fibrosa cystica, which is the end stage of primary hyperparathyroidism. Osteitis fibrosa cystica is associated with the development of brown tumors, which are rare because hyperparathyroidism is now usually diagnosed and treated before symptoms develop. Brown tumors are rarely the first symptom of hyperparathyroidism and can occasionally be mistaken for malignancy.
  
  
  METHODS
  We herein report three cases of primary hyperparathyroidism with an unusual presentation of brown tumors. All three patients were Asian. In the first case, a 42-year-old man was admitted with a mass mimicking a malignant bone neoplasm in the right mandible as the first manifestation of primary hyperparathyroidism. The second case involved a 25-year-old man admitted with a fracture of his right femur. The third case involved a 43-year-old man with multiple brown tumors in both lower limbs. All three patients underwent successful parathyroidectomy for parathyroid adenomas; one case was complicated by a papillary thyroid carcinoma.
  
  
  CONCLUSIONS
  Complete evaluation of the medical history and biochemical and radiographic findings is necessary to achieve a correct diagnosis and avoid unnecessary bone resections in patients with primary hyperparathyroidism.
authors.affiliation: Department of Radiology, The First Affiliated Hospital of the Medical College of Shantou University, Shantou, China. rbhuang1@stu.edu.cn.
authors.forename: Ruibin
authors.initials: R
authors.lastname: Huang
authors.affiliation: Department of Radiology, The First Affiliated Hospital of the Medical College of Shantou University, Shantou, China. ryzhuang@stu.edu.cn.
authors.forename: Ruyao
authors.initials: R
authors.lastname: Zhuang
authors.affiliation: Department of Radiology, The First Affiliated Hospital of the Medical College of Shantou University, Shantou, China. stfsk123@163.com.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Pathology, The First Affiliated Hospital of the Medical College of Shantou University, Shantou, China. 280019000@qq.com.
authors.forename: Tianti
authors.initials: T
authors.lastname: Li
authors.affiliation: Department of Pathology, The First Affiliated Hospital of the Medical College of Shantou University, Shantou, China. hjxcyjhx@21cn.com.
authors.forename: Jiexiong
authors.initials: J
authors.lastname: Huang
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D003952:Diagnostic Imaging / Q000379:methods*; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000175:diagnosis* / Q000209:etiology* / Q000601:surgery; D008297:Male; D010282:Parathyroid Neoplasms / Q000150:complications* / Q000175:diagnosis* / Q000601:surgery; D016896:Treatment Outcome