Paget disease of bone is characterized by which combination?

• A. Abnormal bone remodeling with markedly elevated alkaline phosphatase
• B. Low alkaline phosphatase and dense bones
• C. Primary osteosarcoma with normal alkaline phosphatase
• D. Osteoporosis with low calcium

Answer: (A)

Paget disease of bone is driven by a serious increase in bone turnover, with osteoclasts breaking down bone rapidly and osteoblasts laying down new bone in a disorganized, mosaic pattern. This accelerated remodeling stimulates osteoblastic activity, which makes alkaline phosphatase a prominent serum marker. So the hallmark combination is abnormal, high-turnover bone remodeling with markedly elevated alkaline phosphatase.

Calcium and phosphate levels are usually normal, reflecting turnover rather than a mineral deficiency. Other descriptions don’t fit as well: low alkaline phosphatase points to impaired mineralization disorders like osteomalacia; a dense bone picture with low turnover isn’t the typical Paget pattern; and while bone tumors can raise alkaline phosphatase, they don’t define Paget’s characteristic remodeling process.