A 56-year old man presented with bony pain. X-ray skull lateral view shows:

Ref. Grainger and Allison's Diagnostic Radiology. Page. 483   Pagets disease of bone affects each person differently . It includes : 1 Bones : Pain in the affected bones is the most common symptom of pagets disease of bone.   Skull in Pagets disease osteoporosis circumscripta: large, well-defined lytic lesion cotton wool appearance: mixed lytic and sclerotic lesions of the skull diploic widening: both inner and outer calvarial tables are involved, with the former usually more extensively affected Tam o'Shanter sign: frontal bone enlargement, with the appearance of the skull falling over the facial bones, like a Tam o' Shanter hat