Question 1

What is ICD-10 code C44.520?

Accepted Answer

C44.520 is the ICD-10-CM diagnosis code for squamous cell carcinoma of anal skin. A squamous cell carcinoma (a type of skin cancer arising from outer skin cells) that develops on the anal skin area. C44.520 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering melanoma and other malignant neoplasms of skin (c43-c44).

C44.520 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.

Verify the location is anal skin and not internal anal canal.

Question 2

Is C44.520 an HCC code?

Accepted Answer

No. C44.520 is a billable ICD-10-CM code but does not map to any payment HCC category under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can still be reported on Medicare Advantage encounter data submissions, but it does not contribute to the beneficiary's Risk Adjustment Factor (RAF) score and therefore does not affect the risk-adjusted capitation payment to the plan. V28 reached 100% phase-in for payment year 2026.

Question 3

Is C44.520 billable?

Accepted Answer

Yes. C44.520 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. C44.520 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.

Question 4

What is the V28 vs V24 difference for C44.520?

Accepted Answer

C44.520 does not map to a payment HCC under either the CMS-HCC V28 risk adjustment model or the older V24 model. V28 reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. Because neither community model rewards C44.520 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's V28/V24 community RAF score in either version. Coders should check whether provider documentation supports a more specific child code that does map to a community payment HCC.

Question 5

What should coders know when reporting C44.520?

Accepted Answer

Verify the location is anal skin and not internal anal canal Confirm squamous cell histology is documented in pathology results

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C44.520

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C44.520 ICD-10-CM Code: Squamous cell carcinoma of anal skin

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C44.520

Is C44.520 an HCC code?

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What This Code Means

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