Cotton wool appearance (bone), Radiology Reference Article

The cotton wool appearance is a plain film sign of Paget disease and results from thickened, disorganised trabeculae which lead to areas of sclerosis in a previously lucent area of bone, 

Figure 1 from Does Paget's disease exist in India?: A series of 21 patients.

Paget's Disease of the Skull: A Cotton Wool Appearance

Paget's disease of bone: Report of 11 cases

Panoramic radiograph revealing diffuse, lobular, irregularly shaped

Shepherd crook deformity, Radiology Reference Article

Paget disease (bone), Radiology Reference Article

Cotton wool appearance (bone), Radiology Reference Article

Cotton wool appearance of bone, Radiology Reference Article, Radiopaedia.org

Paget Disease of Bone (Osteitis Deformans) Imaging: Practice Essentials, Radiography, Computed Tomography

Imaging Findings and Evaluation of Metabolic Bone Disease

Skull Base Osteomyelitis: A Comprehensive Imaging Review