60 yrs old male with bony abnormality at upper tibia associated with sensorineural hearing loss. On laboratory examination serum alkaline phosphatase levels are (440 mU/l) elevated and serum Ca and PO4 are normal. Skeletal survey shows ivory vertebrae and cotton wool spots in x-ray skull. Diagnosis is :
a) Fibrous dysplasia
b) Paget disease
c) Osteosclerotic metastasis
Correct answer : b) Paget disease
The age, clinical features and investigation findings are characteristic of Paget’s disease.