M85.50 Aneurysmal bone cyst, unspecified site

Billable ICD-10-CM code, FY2026.

Applies from M85 Other disorders of bone density and structure

Excludes1 (never code together)

• osteogenesis imperfecta (Q78.0)
• osteopetrosis (Q78.2)
• osteopoikilosis (Q78.8)
• polyostotic fibrous dysplasia (Q78.1)

Applies from M85.5 Aneurysmal bone cyst

Excludes2 (not included here)

• aneurysmal cyst of jaw (M27.4)

MS-DRG index

Defines the logic of DRG(s) 553-554 in MDC 08.

Approximate ICD-9-CM (GEMs)

• 733.22 Aneurysmal bone cyst (approximate)

Diagnosis Index entries for M85.50

• Cyst (colloid) (mucous) (simple) (retention) › bone (local) NEC › aneurysmal

Nearby codes

• M85.471 Solitary bone cyst, right ankle and foot
• M85.472 Solitary bone cyst, left ankle and foot
• M85.479 Solitary bone cyst, unspecified ankle and foot
• M85.48 Solitary bone cyst, other site
• M85.5 Aneurysmal bone cyst
• M85.50 Aneurysmal bone cyst, unspecified site (this code)
• M85.51 Aneurysmal bone cyst, shoulder
• M85.511 Aneurysmal bone cyst, right shoulder
• M85.512 Aneurysmal bone cyst, left shoulder
• M85.519 Aneurysmal bone cyst, unspecified shoulder
• M85.52 Aneurysmal bone cyst, upper arm