Fibrous dysplasia (monostotic), left thigh

This diagnosis code represents a benign, localized bone disorder characterized by the replacement of normal bone with fibrous tissue and immature woven bone, specifically affecting a single site (monostotic) in the left thigh. This condition can lead to bone weakness, deformity, and pain.

Use this code when documentation clearly indicates a diagnosis of monostotic fibrous dysplasia located in the left femur. This applies to cases confirmed by imaging (e.g., X-ray, MRI) and/or biopsy findings. It is appropriate for initial diagnoses, follow-up care, and management of complications related to this specific anatomical site.

• Ensure documentation specifies "monostotic" and clearly identifies the "left thigh" (femur) as the affected site.
• Differentiate from polyostotic fibrous dysplasia, which involves multiple bones and has different code assignments.
• Consider additional codes for any associated pathological fractures (M84.452A-S) or other complications.