M85.579 Aneurysmal bone cyst, unspecified ankle and foot

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

• M85.562 Aneurysmal bone cyst, left lower leg
• M85.569 Aneurysmal bone cyst, unspecified lower leg
• M85.57 Aneurysmal bone cyst, ankle and foot
• M85.571 Aneurysmal bone cyst, right ankle and foot
• M85.572 Aneurysmal bone cyst, left ankle and foot
• M85.579 Aneurysmal bone cyst, unspecified ankle and foot (this code)
• M85.58 Aneurysmal bone cyst, other site
• M85.59 Aneurysmal bone cyst, multiple sites
• M85.6 Other cyst of bone
• M85.60 Other cyst of bone, unspecified site
• M85.61 Other cyst of bone, shoulder