Fibrous dysplasia (monostotic), left lower leg

This code describes a benign, localized bone lesion characterized by the replacement of normal bone with fibrous tissue and immature woven bone, specifically affecting a single bone in the left lower leg. This condition results from a developmental anomaly in bone formation, leading to weakened bone structure.

Use this code when documentation confirms a diagnosis of monostotic fibrous dysplasia, explicitly located in the left lower leg (e.g., tibia or fibula). Supporting documentation should include imaging reports (X-ray, CT, MRI) demonstrating characteristic features and, if performed, pathology reports confirming fibrous dysplasia.

• Ensure the documentation specifies "monostotic" (single bone involvement) versus "polyostotic" (multiple bone involvement).
• Verify the exact anatomical location; this code is specific to the left lower leg.
• Distinguish from other bone lesions like non-ossifying fibroma or enchondroma, which have different ICD-10-CM codes.