Fibrous dysplasia (monostotic), unspecified site

This code represents a benign bone disorder characterized by the replacement of normal bone with fibrous tissue and immature woven bone in a single bone. This leads to weakened bone structure, which can result in pain, deformity, or fractures. The "unspecified site" indicates that the specific bone affected is not documented.

Use this code when documentation confirms a diagnosis of monostotic fibrous dysplasia but does not specify the anatomical location. This is appropriate for initial diagnoses where the affected bone has not yet been precisely identified or when the provider explicitly states "unspecified site."

• Avoid using this code if the specific bone affected by fibrous dysplasia is documented; instead, use a more specific code from the M85.0- series.
• Query the provider for clarification on the affected site if possible to allow for more precise coding.
• This code should not be used for polyostotic fibrous dysplasia, which involves multiple bones.