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
Pagets disease
Hyper osteosis frontalis
Fibrous dysplasia
Osteopetrosis