M88.9 Osteitis deformans of unspecified bone

Billable ICD-10-CM code, FY2026.

Applies from M88 Osteitis deformans [Paget's disease of bone]

Excludes1 (never code together)

• osteitis deformans in neoplastic disease (M90.6)

MS-DRG index

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

Approximate ICD-9-CM (GEMs)

• 731.0 Osteitis deformans without mention of bone tumor (approximate)

Code annotations containing back-references to M88.9

Back-references to M88

• Type 1 Excludes: M43 Other deforming dorsopathies ("spinal curvature in Paget's disease of bone [osteitis deformans] (M88.-)")
• Type 1 Excludes: M90.6 Osteitis deformans in neoplastic diseases ("osteitis deformans [Paget's disease of bone] (M88.-)")

Diagnosis Index entries for M88.9

• Osteitis › deformans
• Paget's disease › bone

Nearby codes

• M88.871 Osteitis deformans of right ankle and foot
• M88.872 Osteitis deformans of left ankle and foot
• M88.879 Osteitis deformans of unspecified ankle and foot
• M88.88 Osteitis deformans of other bones
• M88.89 Osteitis deformans of multiple sites
• M88.9 Osteitis deformans of unspecified bone (this code)