M85.639 Other cyst of bone, unspecified forearm

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 M85.6 Other cyst of bone

Excludes1 (never code together)

• cyst of jaw NEC (M27.4)
• osteitis fibrosa cystica generalisata [von Recklinghausen's disease of bone] (E21.0)

MS-DRG index

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

Approximate ICD-9-CM (GEMs)

• 733.29 Other bone cyst (approximate)

Nearby codes

• M85.622 Other cyst of bone, left upper arm
• M85.629 Other cyst of bone, unspecified upper arm
• M85.63 Other cyst of bone, forearm
• M85.631 Other cyst of bone, right forearm
• M85.632 Other cyst of bone, left forearm
• M85.639 Other cyst of bone, unspecified forearm (this code)
• M85.64 Other cyst of bone, hand
• M85.641 Other cyst of bone, right hand
• M85.642 Other cyst of bone, left hand
• M85.649 Other cyst of bone, unspecified hand
• M85.65 Other cyst of bone, thigh