Fibrous dysplasia (monostotic), unspecified hand

This code represents a benign, non-hereditary bone disorder characterized by the replacement of normal bone with fibrous tissue and immature woven bone, specifically affecting a single bone (monostotic) in an unspecified part of the hand. This leads to weakened bone structure, which can result in pain, deformity, or pathological fractures.

Use this code for documented cases of monostotic fibrous dysplasia confirmed to be located in any bone of the hand when the specific bone (e.g., phalanx, metacarpal) is not specified in the medical record. This diagnosis is typically made based on imaging studies (X-ray, CT, MRI) and sometimes biopsy.

• Ensure documentation clearly states "monostotic" and specifies the hand as the affected site.
• If the specific bone in the hand is known (e.g., phalanx, metacarpal), use a more specific code from the M85.04 series.
• Distinguish from polyostotic fibrous dysplasia, which involves multiple bones and has different coding.