ICD-10-CM > M00-M99 > M80-M85 > M85 > M85.0 > M85.03 M85.03 Fibrous dysplasia (monostotic), forearm Non-Billable/Non-Specific Codes M85.031Fibrous dysplasia (monostotic), right forearmM85.032Fibrous dysplasia (monostotic), left forearmM85.039Fibrous dysplasia (monostotic), unspecified forearm