Hyperostosis of skull

This code describes an abnormal thickening or overgrowth of the bone tissue of the skull. It encompasses various forms of skull hyperostosis, which can be localized or generalized, and may or may not be associated with specific syndromes or underlying conditions.

Use this code when documentation explicitly states a diagnosis of hyperostosis of the skull, such as hyperostosis frontalis interna or diffuse calvarial thickening. Supporting documentation should include imaging reports (e.g., X-ray, CT, MRI) confirming the bony overgrowth.

• Do not use this code for isolated osteomas or exostoses of the skull; these have more specific codes.
• Always code any underlying cause or associated systemic condition if known and documented.
• Consider sequencing this code after the primary diagnosis if the hyperostosis is a manifestation of another disease.