M85.68 classifies a bone cyst of the 'other cyst of bone' type occurring at a site that has no dedicated lateralized subcode — including the skull, ribs, vertebrae, neck, and any other skeletal site not captured by M85.60–M85.67 or M85.69.
Verified May 8, 2026 · 3 sources ↓
- Status
- Billable
- Chapter
- 13
- Related CPT
- 10
- Region
- Other
Documentation tips
What should appear in the chart to support M85.68.
Source · Editorial brief grounded in 3 cited references ↓
- Name the specific bone involved (e.g., 'cyst of the T6 vertebral body' or 'rib cyst, 5th rib') — 'other site' is a valid code but the operative or clinic note must confirm the site is not one already enumerated in M85.61–M85.67.
- Document the cyst type explicitly: 'other bone cyst' or equivalent language distinguishes this from aneurysmal bone cysts and simple/unicameral bone cysts, which may map to different codes.
- Record imaging modality and findings that confirm the cystic lesion — X-ray, CT, or MRI description noting thin cortical shell, fluid-filled cavity, absence of soft-tissue mass — to support medical necessity and audit defense.
- If the condition involves the jaw, note whether it is jaw NEC; if so, M27.4 applies, not M85.68 — the provider note should state the affected bone clearly to avoid rerouting.
- When multiple bones are involved, document each site by name and confirm whether a single encounter note supports M85.69 (multiple sites) instead of M85.68.
Related CPT procedures
Procedure codes commonly billed with M85.68. Linking the right diagnosis to the right procedure is what establishes medical necessity.
Source · CMS LCDs · AAOS specialty guidance · claims-pattern analysis
Common coding pitfalls
The recurring mistakes coders make with M85.68 and adjacent codes.
Source · Editorial brief grounded in CDC ICD-10-CM tabular guidance, AAOS coding references, and cited references ↓
- Assigning M85.68 for a jaw cyst — the Excludes1 note at M85.6 prohibits this; jaw cysts NEC belong under M27.4.
- Using M85.68 when M85.69 (multiple sites) is the correct code because the provider documented cysts in two or more distinct skeletal regions — always check whether 'other site' truly means a single non-enumerated site.
- Confusing M85.68 with codes for aneurysmal or unicameral (simple) bone cysts, which have distinct clinical definitions and may carry different code assignments depending on payer LCDs — verify the cyst type in the operative or radiology report.
- Defaulting to M85.60 (unspecified site) when the provider has documented a specific non-enumerated site; M85.68 is more specific and appropriate whenever the exact bone is named.
- Applying a congenital bone disorder code (e.g., Q78.1 for polyostotic fibrous dysplasia) alongside M85.68 — these are Excludes1 conditions and cannot be coded with M85.68 for the same condition.
Clinical context
Source · Editorial summary grounded in 3 cited references ↓
M85.68 is the correct code when a provider documents an 'other' bone cyst (not an aneurysmal bone cyst, not a solitary/simple bone cyst coded elsewhere) at a skeletal location that falls outside the specifically enumerated sites in the M85.6x series. The ICD-10-CM alphabetic index explicitly routes neck, rib, skull, and vertebral cysts here, as well as any 'specified site NEC' under this parent category.
Before assigning M85.68, confirm two exclusions at the parent level: jaw cysts (NEC) map to M27.4, and osteitis fibrosa cystica generalisata (von Recklinghausen's disease of bone) maps to E21.0. At the M85 category level, congenital bone conditions — osteogenesis imperfecta (Q78.0), osteopetrosis (Q78.2), osteopoikilosis (Q78.8), and polyostotic fibrous dysplasia (Q78.1) — are all Excludes1 exclusions and must never be coded here.
If the cyst spans multiple skeletal sites, use M85.69 (multiple sites) instead. If the site is genuinely unknown or undocumented, drop to M85.60 (unspecified site) and query the provider. M85.68 carries no laterality sub-structure because the enumerated 'other' sites (skull, vertebrae, ribs) are midline or bilateral by anatomy; payers will not expect a side modifier on this code.
Sibling codes
Other billable codes under M85.6 (laterality / anatomic variants).
Frequently asked questions
Source · Generated from the editorial pipeline, verified against 3 cited references ↓
01Which bones route to M85.68?
02Can I use M85.68 for a spinal bone cyst?
03What is the difference between M85.68 and M85.69?
04Is a jaw bone cyst coded to M85.68?
05Does M85.68 require a 7th character?
06When should I use M85.60 instead of M85.68?
07Can M85.68 be coded alongside a congenital bone disorder such as polyostotic fibrous dysplasia?
Sources & references
Editorial content was developed using the following public sources. Last verified May 8, 2026.
- 01CDC ICD-10-CM Tabular List 2026
- 02icd10data.comhttps://www.icd10data.com/ICD10CM/Codes/M00-M99/M80-M85/M85-/M85.68
- 03aapc.comhttps://www.aapc.com/codes/icd-10-codes/M85.68
Mira AI Scribe
Mira captures the specific bone name (skull, rib, vertebral level, or other non-enumerated site), cyst characteristics from imaging (cortical thinning, fluid signal, absence of periosteal reaction), and any prior treatment or incidental-finding context. Precise site documentation prevents a downcode to M85.60 (unspecified) and closes the audit gap created by an 'other site' code lacking a named anatomic anchor.
See how Mira captures M85.68 documentation