Fibrous dysplasia (monostotic), right lower leg

This code describes a benign, non-hereditary bone disorder characterized by the replacement of normal bone with fibrous tissue and immature woven bone, affecting a single bone (monostotic) in the right lower leg. This leads to weakened bone, which can result in pain, deformity, or pathological fractures.

Use this code when documentation confirms a diagnosis of monostotic fibrous dysplasia specifically located in the right lower leg (tibia or fibula). This diagnosis is typically supported by imaging studies (X-ray, CT, MRI) showing characteristic bone lesions, and often confirmed by biopsy.

• Ensure documentation specifies "monostotic" and clearly identifies the "right lower leg" as the affected site.
• Differentiate from polyostotic fibrous dysplasia, which involves multiple bones and has different coding.
• Code any associated pathological fractures separately, linking them to the underlying fibrous dysplasia.