M85.521 Aneurysmal bone cyst, right upper arm

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)

Nearby codes

• 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
• M85.521 Aneurysmal bone cyst, right upper arm (this code)
• M85.522 Aneurysmal bone cyst, left upper arm
• M85.529 Aneurysmal bone cyst, unspecified upper arm
• M85.53 Aneurysmal bone cyst, forearm
• M85.531 Aneurysmal bone cyst, right forearm
• M85.532 Aneurysmal bone cyst, left forearm