Hyperostosis of skull

This code describes an abnormal, excessive bone growth on the skull. This condition can manifest as localized thickenings or more diffuse overgrowth of the cranial bones, potentially affecting the shape and integrity of the skull.

Apply this code when documentation explicitly states hyperostosis of the skull, such as in cases of frontal bossing, diffuse calvarial thickening, or other forms of cranial bone overgrowth. Supporting documentation includes imaging reports (e.g., X-ray, CT, MRI) confirming the bony changes and physician notes detailing the finding.

• Do not confuse with Paget's disease of bone (M88.-) unless specifically documented as such.
• Code any underlying cause or associated conditions (e.g., acromegaly, meningioma) in addition to this code.
• Ensure the documentation specifies "skull" as the affected site; hyperostosis can occur in other bones.