M85.09
BillableFibrous dysplasia (monostotic), multiple sites
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M85.09 an HCC code?
No. M85.09 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
M85.09 is the ICD-10-CM diagnosis code for fibrous dysplasia (monostotic), multiple sites. A benign bone condition where fibrous tissue abnormally grows in multiple bones throughout the body. M85.09 sits in the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99), within the section covering disorders of bone density and structure (m80-m85).
M85.09 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
This code indicates polyostotic fibrous dysplasia affecting two or more bones.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for M85.09 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This code indicates polyostotic fibrous dysplasia affecting two or more bones
- •Document all affected sites and consider whether this represents McCune-Albright syndrome, which may have additional coding implications