M85.5
⚠ Non-billable (Header)Aneurysmal bone cyst
Diseases of the musculoskeletal system and connective tissue (M00-M99)
⚠️ This is a category header code — not billable. Use a more specific child code below.
❌ Excludes1
inherited from M85Rules from parent category M85: Other disorders of bone density and structure
- • osteogenesis imperfecta (Q78.0)
- • osteopetrosis (Q78.2)
- • osteopoikilosis (Q78.8)
- • polyostotic fibrous dysplasia (Q78.1)
⚠️ Excludes2
directMay be coded together if both conditions coexist
- • aneurysmal cyst of jaw (M27.4)
Child Codes (10)
M85.50Aneurysmal bone cyst, unspecified siteM85.51Aneurysmal bone cyst, shoulderM85.52Aneurysmal bone cyst, upper armM85.53Aneurysmal bone cyst, forearmM85.54Aneurysmal bone cyst, handM85.55Aneurysmal bone cyst, thighM85.56Aneurysmal bone cyst, lower legM85.57Aneurysmal bone cyst, ankle and footM85.58Aneurysmal bone cyst, other siteM85.59Aneurysmal bone cyst, multiple sites
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CodeM85.5
BillableNo — Header code
ParentM85
CategoryDiseases of the musculoskeletal system and connective tissue (M00-M99)
Excludes14 rule(s)
Excludes21 note(s)
Child codes10
Data Source
CMS ICD-10-CM 2026 Tabular List
Updated October 1, 2025 (FY2026)