Infantile Cortical Hyperostosis

  • Etiology: unknown
  • Imaging: asymmetrical cortical thickening and marrow fibrosis, most commonly affects flat bones in early infancy – mandible (80%) / clavicle / ribs / scapula / skull / ilium, asymmetrical involvement of ulnar diaphysis most common pattern of tubular bone involvement
  • Clinical: present before 9 weeks old, unusual after 6 months old, usually spontaneously resolves in 6-9 months, can have irritability / acute pain / soft tissue swelling / elevated alkaline phosphatase

Radiology Cases of Infantile Cortical Hyperostosis

Radiograph of infantile cortical hyperostosis of clavicle
CXR AP shows marked periosteal reaction involving the left clavicle which is thickened and hyperostotic in appearance. The right clavicle is normal.