60 yrs old male with bony abnormality at upper tibia associated with sensori neural hearing loss. On laboratory examination serum alkaline phosphatase levels are (440 mU/1) elevated and serum Ca++ and PO4– are normal. Skeletal survey shows ivory veebrae and cotton wool spots in x-ray skull. Diagnosis is :

**Core Concept**
Bone disorders can manifest with a variety of systemic symptoms, including sensorineural hearing loss, due to the involvement of the inner ear or the auditory nerve. Elevated serum alkaline phosphatase levels can indicate increased bone turnover.

**Why the Correct Answer is Right**
The patient's presentation of bony abnormality at the upper tibia, sensorineural hearing loss, elevated serum alkaline phosphatase, ivory vertebrae, and cotton wool spots in the skull x-ray is characteristic of Paget's disease of bone. This condition is a localized skeletal disorder that results in an abnormal breakdown and regrowth of bone tissue, leading to deformity and an increased risk of fractures. The sensorineural hearing loss is likely due to the involvement of the inner ear or the auditory nerve, which can be affected by the bone lesions. The elevated serum alkaline phosphatase levels reflect the increased bone turnover associated with Paget's disease.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not related to the patient's presentation of bony abnormality and sensorineural hearing loss.
**Option B:** This option is not consistent with the patient's normal serum calcium and phosphate levels.
**Option C:** This option is not characteristic of Paget's disease, which typically presents with localized bone lesions and elevated alkaline phosphatase levels.

**Clinical Pearl / High-Yield Fact**
Paget's disease of bone can be asymptomatic for many years, and diagnosis is often made incidentally on radiographic examination. It is essential to consider this diagnosis in patients with bony abnormalities and elevated serum alkaline phosphatase levels.

**Correct Answer:** **D**. Paget's disease of bone.

✓ Correct Answer: B. >Paget disease