What is ICD-10 code C72.40?

C72.40 is the ICD-10-CM diagnosis code for Malignant neoplasm of unspecified acoustic nerve. A malignant (cancerous) tumor of the acoustic nerve when the specific side (right or left) is not documented or is bilateral. It belongs to the ICD-10-CM chapter for neoplasms (c00-d49). C72.40 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C72.40 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. C72.40 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. C72.40 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Which HCC does C72.40 map to under V28?

C72.40 maps to CMS-HCC V28 20 (Lung and Other Severe Cancers). The category number and label come from the CMS-HCC V28 model file for payment year 2026.

What does C72.40 pay in RAF?

C72.40 carries a community, non-dual, aged (CNA) RAF weight of 1.136 under CMS-HCC V28 for payment year 2026. The weight comes from the CMS V28 relative-factor file, not a hand-typed table.

What is the V28 vs V24 difference for C72.40?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. For C72.40, V28 maps to Lung and Other Severe Cancers at RAF 1.136 while V24 mapped to Lymphoma and Other Cancers at RAF 0.675. Both models can still appear in legacy data and in payer-specific lookback periods.

What documentation supports C72.40?

Use this code only when laterality is unspecified; prefer C72.41 or C72.42 if side is documented The acoustic nerve (cranial nerve VIII) is also called the vestibulocochlear nerve; verify correct nerve identification Because C72.40 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score. See the MEAT criteria checklist at /meat-criteria for what Monitor, Evaluate, Assess, or Treat looks like in a note. MEAT is generic documentation evidence, not a payer-specific rule.

2026 ICD-10-CM C72.40: Malignant neoplasm

C72.40 maps to CMS-HCC V28 20 (RAF 1.136). Documentation must support MEAT. MEAT criteria · RAF calculator · HCC Buddy coding tools

ICD-10-CM Code View

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Code lookupC72.40Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of eye, brain and other parts of central nervous system (C69-C72)

C72.40

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Malignant neoplasm of unspecified acoustic nerve

A malignant (cancerous) tumor of the acoustic nerve when the specific side (right or left) is not documented or is bilateral.

Buddy Insight

Malignant neoplasm of the unspecified acoustic nerve represents cancer of cranial nerve VIII (vestibulocochlear nerve) without laterality documentation.

CMS-HCC V28

Mapped

HCC 20

Lung and Other Severe Cancers

RAF 1.136

CMS-HCC V24

Mapped

HCC 10

Lymphoma and Other Cancers

RAF 0.675

ACA/HHS

Mapped

HCC 9

HHS-HCC 9

Varies by metal level

ESRD/PACE

Mapped

HCC 10

Lymphoma and Other Cancers

RAF 0.111

RXHCC

Mapped

HCC 22

Cancer, Other Specified Sites

RAF 0.124

Code Book Path

Official

C72Malignant neoplasm of spinal cord, cranial nerves and other parts of central nervous system

C72.4Malignant neoplasm of acoustic nerve

C72.40Malignant neoplasm of unspecified acoustic nerve

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for C72.40 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for C72.40 in this effective period.

Related Child Codes

Official

C72.41Malignant neoplasm of right acoustic nerve

C72.42Malignant neoplasm of left acoustic nerve

Includes

Official

ICD-10-CM does not list Includes notes for C72.40 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for C72.40 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C72.40 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for C72.40 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for C72.40 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Pathology confirming malignancy — most acoustic nerve tumors are benign; malignancy must be verified

Laterality documentation — query provider to assign C72.41 or C72.42 when possible

Audiometric evaluation results

Imaging (MRI) documenting tumor size and extent

MEAT Support

HCC Buddy guidance

Pathology confirming malignancy — most acoustic nerve tumors are benign; malignancy must be verified

Laterality documentation — query provider to assign C72.41 or C72.42 when possible

Audiometric evaluation results

Imaging (MRI) documenting tumor size and extent

Audit Caution

HCC Buddy guidance

Coding benign vestibular schwannomas (acoustic neuromas) as malignant — this is the most common error with acoustic nerve tumors

Using unspecified laterality when MRI clearly shows which side is affected

Failing to verify malignancy in pathology report — the vast majority of CN VIII tumors are benign

Confusing acoustic neuroma (benign D33.3) with malignant acoustic nerve tumor

Common Mistakes

HCC Buddy guidance

C72.41/C72.42 — Right/left acoustic nerve: Use lateralized codes when side is documented

D33.3 — Benign neoplasm of cranial nerves: Vestibular schwannomas (acoustic neuromas) are benign and far more common

D43.3 — Neoplasm of uncertain behavior of cranial nerves: Use when malignancy is not confirmed

H93.10 — Tinnitus, unspecified ear: A symptom, not a diagnosis — do not confuse with the underlying tumor

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is C72.40 an HCC code?

Yes. C72.40 (Malignant neoplasm of unspecified acoustic nerve) maps to Lung and Other Severe Cancers under the CMS-HCC V28 risk adjustment model (and Lymphoma and Other Cancers under V24), with a community non-dual aged RAF of 1.136. It is billable for payment year 2026.

Coder answer: C72.40 is billable and maps to V28 HCC 20, Lung and Other Severe Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: C72.40
Description: Malignant neoplasm of unspecified acoustic nerve
HCC (V28): HCC 20 — Lung and Other Severe Cancers
RAF: 1.136
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 20, Lung and Other Severe Cancers

1.136

V24HCC 10, Lymphoma and Other Cancers

0.675

ESRDHCC 10, Lymphoma and Other Cancers

0.111

RxHCCHCC 22, Cancer, Other Specified Sites

0.124

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

Work C72.40 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for C72.40

For C72.40 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed C72.40 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

C72.40 is the ICD-10-CM diagnosis code for malignant neoplasm of unspecified acoustic nerve. A malignant (cancerous) tumor of the acoustic nerve when the specific side (right or left) is not documented or is bilateral. C72.40 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of eye, brain and other parts of central nervous system (c69-c72).

Under the CMS-HCC V28 risk adjustment model, C72.40 maps to Lung and Other Severe Cancers (HCC 20) with a community, non-dual, aged base RAF weight of 1.136. Under the older CMS-HCC V24 model, C72.40 maps to Lymphoma and Other Cancers (HCC 10) with a community, non-dual, aged base RAF weight of 0.675. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

Use this code only when laterality is unspecified; prefer C72.41 or C72.42 if side is documented. Because C72.40 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for C72.40 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Use this code only when laterality is unspecified; prefer C72.41 or C72.42 if side is documented
•The acoustic nerve (cranial nerve VIII) is also called the vestibulocochlear nerve; verify correct nerve identification

Clinical Significance

Malignant neoplasm of the unspecified acoustic nerve represents cancer of cranial nerve VIII (vestibulocochlear nerve) without laterality documentation. While most acoustic nerve tumors are benign vestibular schwannomas, malignant variants do occur and carry significant morbidity including hearing loss and facial nerve dysfunction. The unspecified laterality should prompt a provider query.

Documentation Requirements

✓Pathology confirming malignancy — most acoustic nerve tumors are benign; malignancy must be verified
✓Laterality documentation — query provider to assign C72.41 or C72.42 when possible
✓Audiometric evaluation results
✓Imaging (MRI) documenting tumor size and extent
✓Documentation distinguishing from benign vestibular schwannoma (acoustic neuroma)

Commonly Confused Codes

•C72.41/C72.42: Right/left acoustic nerve: Use lateralized codes when side is documented
•D33.3: Benign neoplasm of cranial nerves: Vestibular schwannomas (acoustic neuromas) are benign and far more common
•D43.3: Neoplasm of uncertain behavior of cranial nerves: Use when malignancy is not confirmed
•H93.10: Tinnitus, unspecified ear: A symptom, not a diagnosis: do not confuse with the underlying tumor