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Cotton-wool skull is a descriptive radiological term most commonly associated with Paget disease (bone) , particularly in its skull involvement.
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Paget disease (bone): It results from abnormal bone remodeling, with accelerated bone resorption followed by chaotic bone deposition.
| Modality | Imaging features |
|---|---|
| XR/CT | • Patchy, fluffy, cloud-like sclerotic areas. |
| • Involves calvarium, especially frontal and parietal bones. | |
| • May show thickened cortical bone and expanded diploic space. | |
| MR | • Useful if neurological complications suspected. |
| Bone scan | • Shows increased radiotracer uptake in active disease |
Radiography of the skull (Panel A) showed thickening of the outer and inner tables of the cranial bones, widening of the diploë, and a “cotton wool” appearance caused by irregular areas of sclerosis (arrows). CT (Panel B) confirmed bony expansion, cortical bone thickening, and irregular areas of sclerosis (arrows). These imaging findings reflect the mixed osteolytic & osteoblastic phases of Paget's disease, resulting in accelerated bone turnover with bone deposition and expansion. The patient was treated with alendronate, which resulted in improvement in frontal headache.
Bhargava, P., & Maki, J. H. (2010). “Cotton Wool” Appearance of Paget’s Disease. New England Journal of Medicine, 363(6), e9. https://doi.org/10.1056/NEJMicm0912945
| Conditions | Imaging features |
|---|---|
| ‣ | Ground-glass appearance, not truly cotton-wool |
| ‣ | Particularly from prostate or breast, though usually focal sclerotic or lytic |
| ‣ | Diffuse sclerosis, “bone-within-bone” appearance |
