24-year-old male, slowly progressive swelling of rib. X- ray shows circumscribed perturbation of homogenous density, thin corticalis. Resection.
- Fibro-osseous lesion: focal increase in density of primitive fibrous bone from blunt fibrous ground tissue. Collagen fibresextend into the bone.
- The fibrous bone forms an unusually bent or round bar or cusp which often appear like the letters (C, O, L, T, Y; Chinese letter)
- Osteoblasts are missing.
Clinically: monostotic, rarely polystotic skeleton. The latter form is occasionally associated with “café- au-lait” patches and precocious puberty: Albright syndrome.