A 48-year-old man who had recently immigrated to France and had not yet established routine medical care presented to the emergency department with shortness of breath. He had a history of end-stage renal disease for which hemodialysis(血液透析) had been initiated 10 years earlier. A physical examination showed mandibular prominence(下颌隆起), thoracic kyphosis(胸椎后凸), and crackles（裂纹） in both lungs. Laboratory studies showed a calcium（钙） level of 1.9 mmol per liter (7.6 mg per deciliter) (normal range, 2.2 to 2.6 mmol per liter [8.8 to 10.4 mg per deciliter]), a phosphate level （磷酸盐）of 0.96 mmol per liter (2.97 mg per deciliter) (normal range, 0.81 to 1.58 mmol per liter [2.51 to 4.89 mg per deciliter]), a 25-hydroxyvitamin D（25-羟基维生素D） level of 13 nmol per liter (5.2 ng per milliliter) (normal range, 75 to 175 nmol per liter [30 to 70 ng per milliliter]), and a parathyroid hormone（甲状旁腺激素） level of 4081 ng per liter (normal range, 11.5 to 78.4). Computed tomography (Panel A) and three-dimensional reconstruction (Panel B) of the face revealed mandibular hypertrophy（下颌肥大） and a heterogeneous（异质的） appearance of the bone, with both cystic lesions（囊性病变） and patches of osteolysis（骨质溶解斑块）. Similar bony lesions were found in the spine, iliac bone（髂骨）, and femur（股骨）. Osteitis fibrosa cystica（囊性纤维性骨炎） is a skeletal disorder that is caused by sustained hyperparathyroidism（甲状旁腺功能亢进）, often due to chronic renal failure, resulting in the formation of cystlike tumors（囊性肿瘤） in the bone. Treatment with cinacalcet（盐酸西那卡塞片） and vitamin D supplementation（补充维生素D） were started. His shortness of breath resolved after hemodialysis was reinitiated（恢复）. At a follow-up visit 6 months after treatment was initiated, the parathyroid hormone（甲状旁腺激素） level had decreased to 1743 ng per liter and the 25-hydroxyvitamin D level had returned to a normal level, but the bone lesions had not regressed.