What is ICD-10 code C79.2?

C79.2 is the ICD-10-CM diagnosis code for Secondary malignant neoplasm of skin. Cancer that has spread to the skin from a primary cancer in another part of the body. It belongs to the ICD-10-CM chapter for neoplasms (c00-d49). C79.2 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C79.2 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. C79.2 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. C79.2 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 C79.2 map to under V28?

C79.2 maps to CMS-HCC V28 HCC 18 (Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid). The category numbers, labels, and conditions come from the CMS-HCC V28 model file for payment year 2026.

2026 ICD-10-CM C79.2: Secondary malignant neoplasm

C79.2 maps to CMS-HCC V28 18. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · free HCC coding tools

ICD-10-CM Code View

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Code lookupC79.2

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of ill-defined, other secondary and unspecified sites (C76-C80)

C79.2

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

Secondary malignant neoplasm of skin

Cancer that has spread to the skin from a primary cancer in another part of the body.

Buddy Insight

Secondary malignant neoplasm of skin indicates metastatic cancer has spread to the skin from an internal primary cancer.

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

Mapped

HCC 18

Cancer Metastatic to Bone, Ot...

Code-level coefficient reference

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

Mapped

HCC 008

HHS-HCC 008 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 10

Lymphoma and Other Cancers

Code-level coefficient reference

RXHCC

Mapped

HCC 18

Secondary Cancer of Lung, Liv...

Code-level coefficient reference

Code Book Path

Official

C79Secondary malignant neoplasm of other and unspecified sites C79.2Secondary malignant neoplasm of skin

Inclusion Terms

Official

No inclusion terms are included in this display for C79.2. Check the code and parent instructions in the Code Book.

Excludes 2

Official

No Excludes 2 notes are included in this display for C79.2. Check the code and parent instructions in the Code Book.

Related Codes

Official

C79.0Secondary malignant neoplasm of kidney and renal pelvis C79.1Secondary malignant neoplasm of bladder and other and unspecified urinary organs C79.3Secondary malignant neoplasm of brain and cerebral meninges C79.4Secondary malignant neoplasm of other and unspecified parts of nervous system C79.5Secondary malignant neoplasm of bone and bone marrow

Includes

Official

No Includes notes are included in this display for C79.2. Check the code and parent instructions in the Code Book.

Excludes 1

Official

secondary Merkel cell carcinoma (C7B.1)
secondary carcinoid tumors (C7B.-)Inherited from C79
secondary neuroendocrine tumors (C7B.-)Inherited from C79

Code First

Official

No Code First sequencing instructions are included in this display for C79.2. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for C79.2. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for C79.2. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Primary cancer site documented and coded separately

Anatomical location of the cutaneous metastasis

Biopsy confirmation distinguishing metastatic deposits from primary skin cancers

Number and distribution of skin lesions

MEAT Support

HCC Buddy guidance

Primary cancer site documented and coded separately

Anatomical location of the cutaneous metastasis

Biopsy confirmation distinguishing metastatic deposits from primary skin cancers

Number and distribution of skin lesions

Audit Caution

HCC Buddy guidance

Confusing skin metastases from internal cancers with primary skin cancers (basal cell carcinoma, squamous cell carcinoma, melanoma)

Coding satellite or in-transit melanoma lesions as C79.2 instead of using melanoma staging codes

Not obtaining biopsy confirmation to distinguish new primary skin cancer from metastatic deposits

Failing to code the primary cancer site when cutaneous metastases are identified

Common Mistakes

HCC Buddy guidance

C43.0-C43.9 — Primary malignant melanoma of skin; melanoma is a primary skin cancer, not metastatic from another site

C44.0-C44.99 — Other primary malignant neoplasms of skin; basal cell and squamous cell carcinomas are primary, not secondary

C79.89 — Secondary malignant neoplasm of other specified sites; skin metastases have their own specific code C79.2

D03.0-D03.9 — Melanoma in situ; this is a pre-invasive primary lesion, not metastatic disease

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 C79.2 an HCC code?

Yes. C79.2 (Secondary malignant neoplasm of skin) maps to HCC 18, Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 2.341. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: C79.2 is billable and maps to V28 HCC 18, Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: C79.2
Description: Secondary malignant neoplasm of skin
HCC (V28): HCC 18 — Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid
RAF reference coefficient: 2.341
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 18, Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid

2.341

ESRDHCC 10, Lymphoma and Other Cancers

Not separately weighted

RxHCCHCC 18, Secondary Cancer of Lung, Liver, Brain, and Other Sites

Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. 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 context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work C79.2 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for C79.2

For C79.2, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

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

Coder workflow notes

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What This Code Means

C79.2 is the ICD-10-CM diagnosis code for secondary malignant neoplasm of skin. Cancer that has spread to the skin from a primary cancer in another part of the body. C79.2 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of ill-defined, other secondary and unspecified sites (c76-c80).

Under the CMS-HCC V28 risk adjustment model, C79.2 maps to Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid (HCC 18) with a source-labeled community, non-dual, aged reference coefficient of 2.341. No V24 mapping is shown for C79.2; use the applicable model and payment year when reviewing the V28 mapping. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

Document the specific anatomical location of the skin lesion if possible, as this may affect treatment planning and prognosis. For C79.2, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. 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, source-labeled coefficient references, and MEAT documentation criteria for C79.2 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Document the specific anatomical location of the skin lesion if possible, as this may affect treatment planning and prognosis
•Ensure the primary cancer site is coded separately to provide complete clinical picture of metastatic disease

Clinical Significance

Secondary malignant neoplasm of skin indicates metastatic cancer has spread to the skin from an internal primary cancer. Cutaneous metastases are relatively uncommon but carry significant prognostic implications, often indicating widely disseminated disease. The most common primary cancers that metastasize to skin include breast, lung, colorectal, and melanoma.

Documentation Requirements

✓Primary cancer site documented and coded separately
✓Anatomical location of the cutaneous metastasis
✓Biopsy confirmation distinguishing metastatic deposits from primary skin cancers
✓Number and distribution of skin lesions
✓Clinical description — nodular, inflammatory, or ulcerating presentation

Excludes 1, Do NOT code together

secondary Merkel cell carcinoma (C7B.1)

Commonly Confused Codes

•C43.0-C43.9: Primary malignant melanoma of skin; melanoma is a primary skin cancer, not metastatic from another site
•C44.0-C44.99: Other primary malignant neoplasms of skin; basal cell and squamous cell carcinomas are primary, not secondary
•C79.89: Secondary malignant neoplasm of other specified sites; skin metastases have their own specific code C79.2
•D03.0-D03.9: Melanoma in situ; this is a pre-invasive primary lesion, not metastatic disease