What is ICD-10 code C54.1?

C54.1 is the ICD-10-CM diagnosis code for Malignant neoplasm of endometrium. Cancer that starts in the endometrium, which is the inner lining of the uterus. This is the most common type of uterine cancer. It belongs to the ICD-10-CM chapter for neoplasms (c00-d49). C54.1 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C54.1 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. C54.1 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. C54.1 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 C54.1 map to under V28?

C54.1 maps to CMS-HCC V28 HCC 23 (Prostate, Breast, and Other Cancers and Tumors). The category numbers, labels, and conditions come from the CMS-HCC V28 model file for payment year 2026.

2026 ICD-10-CM C54.1: Malignant neoplasm

C54.1 maps to CMS-HCC V28 23. A source-labeled RAF reference is available. Documentation must support MEAT. MEAT criteria · RAF Calculator · HCC Buddy coding tools

ICD-10-CM Code View

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Code lookupC54.1Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of female genital organs (C51-C58)

C54.1

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

Malignant neoplasm of endometrium

Cancer that starts in the endometrium, which is the inner lining of the uterus. This is the most common type of uterine cancer.

Buddy Insight

Malignant neoplasm of the endometrium is the most common gynecological cancer in developed countries, with endometrioid adenocarcinoma being the predominant histological type.

CMS-HCC V28

Mapped

HCC 23

Prostate, Breast, and Other C...

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 012

HHS-HCC 012 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 12

Breast/Prostate/and Other Can...

Code-level coefficient reference

RXHCC

N/A

—

Not risk-adjusted for this model/period.

Not mapped

Code Book Path

Official

C54Malignant neoplasm of corpus uteri

C54.1Malignant neoplasm of endometrium

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for C54.1 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for C54.1 in this effective period.

Related Child Codes

Official

C54.0Malignant neoplasm of isthmus uteri

C54.2Malignant neoplasm of myometrium

C54.3Malignant neoplasm of fundus uteri

C54.8Malignant neoplasm of overlapping sites of corpus uteri

C54.9Malignant neoplasm of corpus uteri, unspecified

Includes

Official

ICD-10-CM does not list Includes notes for C54.1 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for C54.1 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C54.1 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for C54.1 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for C54.1 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Histological type specified (endometrioid, serous, clear cell, mixed, carcinosarcoma)

Tumor grade (Grade 1, 2, or 3)

FIGO staging

Depth of myometrial invasion (less than or greater than 50%)

MEAT Support

HCC Buddy guidance

Histological type specified (endometrioid, serous, clear cell, mixed, carcinosarcoma)

Tumor grade (Grade 1, 2, or 3)

FIGO staging

Depth of myometrial invasion (less than or greater than 50%)

Audit Caution

HCC Buddy guidance

Confusing endometrial hyperplasia (N85.0) with endometrial cancer — hyperplasia is a precursor condition

Not distinguishing between endometrial cancer extending into myometrium versus primary myometrial cancer

Using uterus unspecified (C55) when endometrium is specifically documented

Failing to capture the histological type which impacts treatment (serous and clear cell types are high-grade with different treatment protocols)

Common Mistakes

HCC Buddy guidance

C54.2 — Malignant neoplasm of myometrium; different uterine layer — endometrium is the inner lining, myometrium is the muscle layer

C54.9 — Corpus uteri, unspecified; less specific when endometrium is clearly identified

C55 — Uterus, part unspecified; use only when the specific uterine structure cannot be determined

D07.0 — Carcinoma in situ of endometrium; endometrial intraepithelial neoplasia, not invasive cancer

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 C54.1 an HCC code?

Yes. C54.1 (Malignant neoplasm of endometrium) maps to HCC 23, Prostate, Breast, and Other Cancers and Tumors under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.186. 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: C54.1 is billable and maps to V28 HCC 23, Prostate, Breast, and Other Cancers and Tumors. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: C54.1
Description: Malignant neoplasm of endometrium
HCC (V28): HCC 23 — Prostate, Breast, and Other Cancers and Tumors
RAF reference coefficient: 0.186
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 23, Prostate, Breast, and Other Cancers and Tumors

0.186

ESRDHCC 12, Breast/Prostate/and Other Cancers and Tumors

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 C54.1 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT Criteria for C54.1

For C54.1 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 C54.1 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

C54.1 is the ICD-10-CM diagnosis code for malignant neoplasm of endometrium. Cancer that starts in the endometrium, which is the inner lining of the uterus. This is the most common type of uterine cancer. C54.1 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of female genital organs (c51-c58).

Under the CMS-HCC V28 risk adjustment model, C54.1 maps to Prostate, Breast, and Other Cancers and Tumors (HCC 23) with a source-labeled community, non-dual, aged reference coefficient of 0.186. No V24 mapping is shown for C54.1; use the applicable model and payment year when reviewing the V28 mapping. 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. 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.

Verify histology type (adenocarcinoma, sarcoma, etc.) as it may affect treatment and prognosis. Because C54.1 maps to an HCC category, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) before the diagnosis is used for risk adjustment. 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 C54.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Verify histology type (adenocarcinoma, sarcoma, etc.) as it may affect treatment and prognosis
•Confirm laterality is not applicable; use this code for endometrial cancers regardless of location within the uterus

Clinical Significance

Malignant neoplasm of the endometrium is the most common gynecological cancer in developed countries, with endometrioid adenocarcinoma being the predominant histological type. Risk factors include obesity, unopposed estrogen exposure, nulliparity, and tamoxifen use. Early detection through evaluation of abnormal uterine bleeding typically results in favorable outcomes.

Documentation Requirements

✓Histological type specified (endometrioid, serous, clear cell, mixed, carcinosarcoma)
✓Tumor grade (Grade 1, 2, or 3)
✓FIGO staging
✓Depth of myometrial invasion (less than or greater than 50%)
✓Cervical stromal involvement (upstages to stage II)
✓Lymphovascular space invasion
✓Lymph node status (pelvic and para-aortic)
✓Estrogen and progesterone receptor status if documented
✓Mismatch repair or microsatellite instability status if available

Commonly Confused Codes

•C54.2: Malignant neoplasm of myometrium; different uterine layer: endometrium is the inner lining, myometrium is the muscle layer
•C54.9: Corpus uteri, unspecified; less specific when endometrium is clearly identified
•C55: Uterus, part unspecified; use only when the specific uterine structure cannot be determined
•D07.0: Carcinoma in situ of endometrium; endometrial intraepithelial neoplasia, not invasive cancer
•N85.0: Endometrial hyperplasia; benign condition, not malignancy