Question

A 65-year-old man presents with enlarged hat size, shin pain, elevated alkaline phosphatase, and normal calcium and PTH levels. X-ray reveals mixed lytic and sclerotic bone lesions. What is the most likely diagnosis?

• A. Paget's disease
• B. Primary hyperparathyroidism
• C. Osteomalacia
• D. Bone metastasis

Hint:

Elderly patient with bone pain, enlarged skull, raised ALP, and normal calcium = Paget's disease of bone.

Answer 1

The Correct Option is A

Concept: Paget's disease of bone is a disorder of excessive and disorganized bone remodeling. It commonly affects elderly patients and causes bone pain, deformity, increased skull size, and raised alkaline phosphatase with normal calcium and phosphate.

Step 1: Identify the clinical clues.
The patient has: \[ \text{Enlarged hat size + shin pain} \] This indicates skull and long bone involvement.

Step 2: Interpret laboratory findings.
Alkaline phosphatase is elevated, but calcium and PTH are normal: \[ ALP \uparrow,\quad Ca^{2+} \text{ normal},\quad PTH \text{ normal} \] This pattern is typical of Paget's disease.

Step 3: Use radiological clue.
Mixed lytic and sclerotic bone lesions occur due to abnormal bone resorption and formation. Therefore, the most likely diagnosis is: \[ \text{Paget's disease} \]