M27.0 vs M27.4
M27.0 and M27.4 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.
The official note, declared on M27.4
latent bone cyst of jaw (M27.0)
M27.0
Developmental disorders of jaws
Billable
- Chapter 13
- Diseases of the musculoskeletal system and connective tissue
- Section
- M26-M27
Use when the record says
- Latent bone cyst of jaw
- Stafne's cyst
- Torus mandibularis
- Torus palatinus
Indexed under
- Stafne's cyst or cavity
- Torus (mandibularis) (palatinus)
- Cyst › Stafne's (colloid) (mucous) (simple) (retention)
- Disorder › jaw, developmental (of)
- Cyst › boneNEC › specified type NEC › jaw › latent (colloid) (mucous) (simple) (retention)
M27.4
Other and unspecified cysts of jaw
Not billable
- Chapter 13
- Diseases of the musculoskeletal system and connective tissue
- Section
- M26-M27
Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027