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Key Takeaways
ICD-10 Code C54.1 describes malignant neoplasm of the endometrium, the inner lining of the uterine corpus.
C54.1 is a billable, specific ICD-10-CM code valid for FY2026 claims submission effective October 1, 2025.
Use C55 only when the uterine site is unspecified – C54.1 requires documented endometrial involvement.
Pabau’s claims management software links ICD-10 codes directly to billing workflows, reducing manual transcription errors for codes like C54.1.
ICD-10 Code C54.1 is the billable, site-specific diagnostic code for malignant neoplasm of the endometrium, the inner lining of the uterine corpus. Endometrial cancer is the most common gynecologic malignancy in the United States. Using the unspecified uterine code C55 when the chart documents endometrial involvement is one of the most frequently flagged errors in gynecologic oncology audits.
This reference covers the official code descriptor, FY2026 billable status, the C54 hierarchy, documentation requirements, common coding errors, and the CPT codes most frequently submitted alongside C54.1. For practices managing gynecologic oncology billing, claims management software that embeds ICD-10 lookup at the point of care can significantly reduce the manual transcription step between diagnosis and submission.
C54.1 code details at a glance
The table below covers the core reference data for ICD-10 Code C54.1 as published in the FY2026 ICD-10-CM tabular list, effective October 1, 2025.
The CDC/NCHS ICD-10-CM web tool provides the authoritative annual tabular list. Always verify billable status against the current fiscal year before submission, since code additions and revisions take effect each October 1.
Clinical description: Malignant neoplasm of the endometrium
The endometrium is the mucosal lining of the uterine corpus, the body of the uterus. Endometrial cancer arises from this lining and is distinct from myometrial or cervical malignancies. For coding purposes, the distinction is entirely anatomical: C54.1 requires the physician to document that the primary malignancy involves the endometrium specifically, not simply the uterus in general.
The most common histological subtype is endometrioid adenocarcinoma, though other types (serous, clear cell, carcinosarcoma) also map to C54.1 when the endometrium is the confirmed primary site. Histological type is captured separately using morphology codes from the neoplasm table. C54.1 identifies the anatomical site. Maintaining accurate structured patient records from diagnosis through treatment supports the documentation trail payers require.
ICD-10-CM code hierarchy: Where C54.1 fits
C54.1 sits within the C54 parent category, which covers malignant neoplasms of the corpus uteri as a whole. The sibling codes below help coders select the correct level of specificity.
Applicable to and includes notes for C54.1
The ICD-10-CM tabular list includes an “Applicable To” note under C54.1 that clarifies the conditions captured by this code. Per the official tabular list, C54.1 applies to:
- Adenocarcinoma of the endometrium
- Endometrial carcinoma
- Cancer of the endometrium
- Endometrioid carcinoma of corpus uteri
Any histological subtype of malignant neoplasm where the primary anatomical site is confirmed as the endometrium falls under C54.1. Coders should not use a morphology-based code in place of C54.1; the ICD-10-CM guidelines require the site code to be reported, with morphology codes used as supplementary where required by the facility or payer.
Excludes notes and code-first guidance
C54.1 does not carry an Excludes1 note of its own, but coders should be aware of the broader exclusions that apply to the C54 category and the C51-C58 block.
- Excludes1 (parent block C51-C58): Melanoma and other malignant neoplasms of skin of female genital organs (these are classified elsewhere in C43-C44)
- Use additional code where applicable: secondary malignant neoplasm of lymph nodes or other organs if documented as involved
- Code also: personal history of malignant neoplasm of female genital organs (Z85.40-Z85.44) where applicable for follow-up encounters
When the encounter is for follow-up after completed treatment with no evidence of disease, report Z08 (Encounter for follow-up examination after completed treatment for malignant neoplasm) as the principal diagnosis, with C54.1 sequenced as an additional code. When active treatment is ongoing, C54.1 is the principal diagnosis.
Documentation requirements for C54.1
Payers reviewing claims for C54.1 look for documentation that supports the site specificity the code requires. Missing any of these elements is the fastest route to a denial or audit flag.
- Confirmed malignancy of the endometrium: Pathology report or physician attestation identifying the endometrium as the primary site
- Histological type: Adenocarcinoma, serous, clear cell, or other subtype documented in the operative or pathology report
- Primary vs. secondary: State whether this is a primary malignancy (C54.1) or a secondary/metastatic site; do not use C54.1 for metastasis to the endometrium
- FIGO stage (where known): FIGO staging is standard for gynecologic oncology and should appear in the operative or oncology note; additional ICD-10-CM codes may be required to capture extent of disease
- Encounter type: Specify whether the encounter is for active treatment, follow-up, or surveillance; this determines sequencing
Practices that use digital clinical documentation can structure oncology notes to capture these elements at the point of care rather than retrospectively. For gynecologic oncology workflows, OB/GYN EMR software with integrated ICD-10 lookup removes the manual step of cross-referencing code books during note completion.
Good HIPAA-compliant recordkeeping also ensures that documentation supporting C54.1 is stored securely and is accessible for audit purposes. Reviewing a gynecology EHR comparison can help practices weigh which platform handles oncology-specific documentation best.
Pro Tip
Always document the endometrial site explicitly in the operative or pathology note rather than relying on the diagnosis line alone. Payers auditing C54.1 claims look for site confirmation in the supporting documentation itself, since the claim form alone doesn’t establish it.
Common coding errors and how to avoid them
Audits of gynecologic oncology claims consistently surface the same set of C54.1 errors. Most stem from insufficient documentation at the time of service rather than deliberate miscoding.
- Using C55 when the site is documented: C55 is for malignant neoplasm of uterus, part unspecified. If the physician has confirmed endometrial involvement in any documentation, C54.1 is required. Using C55 when the record supports C54.1 signals incomplete coding and may reduce reimbursement.
- Omitting staging codes: FIGO staging for endometrial cancer often requires additional ICD-10-CM codes to capture extent of disease. Reporting C54.1 without staging codes where documentation supports staging leaves the claim incomplete for many oncology payers.
- Coding a secondary malignancy as C54.1: C54.1 describes a primary malignancy only. If the endometrium is a site of metastasis, the appropriate code is from the C79.x range (secondary malignant neoplasm). Always query the physician when primary versus secondary status is unclear.
- Using C54.9 or C54.8 instead of C54.1: When the pathology report specifies endometrial involvement, C54.9 (unspecified corpus) and C54.8 (overlapping sites) are not appropriate. Code to the highest level of specificity the documentation supports.
Robust clinical documentation compliance programs that train coders and clinicians together are the most effective way to catch these errors before submission. The AAPC ICD-10-CM code lookup provides additional coding guidance and crosswalk references for the C54 family.
Endometrial cancer staging codes for C54.1
FIGO staging is the standard classification system for endometrial cancer. ICD-10-CM does not have built-in FIGO staging codes within C54.1 itself, but payers and cancer registries typically require extent-of-disease codes alongside C54.1 to fully characterize the encounter. The table below maps FIGO stages to the relevant ICD-10-CM supplementary codes.
Staging-code specifics should always be confirmed against current CMS ICD-10-CM guidelines before submission, as payer-specific requirements for staging codes vary. The WHO ICD-10 browser provides the international classification context underlying the U.S. ICD-10-CM adaptation.
CPT codes commonly used alongside C54.1
Knowing which CPT procedure codes are typically paired with C54.1 helps coders build complete claims and anticipate medical necessity reviews. The table below reflects common procedural coding patterns in endometrial cancer care. Always verify specific pairings against current AMA CPT coding guidelines and payer LCDs before submission.
Related ICD-10-CM codes for endometrial and uterine cancer
Coders working in gynecologic oncology regularly encounter the codes in the table below as companions to, or distinctions from, ICD-10 Code C54.1. Practices that manage broader gynecologic caseloads alongside oncology cases often rely on pelvic health software to keep documentation consistent across specialties. The same personal-history logic applies elsewhere in oncology coding, such as Z85.3 for a patient’s earlier breast cancer diagnosis.
Streamline your gynecologic oncology billing
Pabau links ICD-10 diagnosis codes directly to your billing and claims workflows, so your team codes C54.1 at the point of care, not in a separate lookup. See how Pabau supports OB/GYN and oncology practices.
Pro Tip
Set up a macro or structured template in your clinical notes system that automatically prompts for FIGO stage, primary versus secondary status, and histological type whenever C54.1 is selected. This captures the details up front, before claims are submitted.
Conclusion
Endometrial cancer claims denied or flagged for audit almost always trace back to one of two problems: using C55 when the site is documented, or submitting C54.1 without staging codes when the operative or pathology report supports them. Both stem from incomplete documentation at the point of care.
Practices that embed ICD-10 code selection into the clinical documentation workflow catch these errors before a claim is submitted. Pabau’s claims management software links diagnosis codes directly to the billing pipeline, cutting the manual transcription step where most C54.1 errors occur. Practices still comparing platforms can start with this medical billing software roundup. To see how Pabau supports OB/GYN and oncology billing, book a demo.
Continue your research
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Want to reduce claim denials across your practice? Client management features in Pabau help structure patient data to support accurate, complete coding at every encounter.
Frequently asked questions
What is ICD-10 Code C54.1 used for?
ICD-10 Code C54.1 is the billable ICD-10-CM diagnosis code for malignant neoplasm of the endometrium, used to report primary endometrial cancer on claims and clinical documentation. It identifies the endometrium (the inner lining of the uterine corpus) as the confirmed primary site of malignancy, distinguishing it from other uterine cancers coded under C54.0, C54.2, C54.9, or C55.
Is C54.1 a billable ICD-10 code for FY2026?
Yes. C54.1 is a billable, specific ICD-10-CM code valid for FY2026 claims submission, effective October 1, 2025. It has not been revised or retired in the FY2026 update. Confirm current status via the CDC/NCHS ICD-10-CM web tool before each fiscal year’s claims begin.
What is the difference between C54.1 and C55?
C54.1 requires documentation confirming the endometrium as the primary site; C55 is used only when the site within the uterus cannot be determined from available documentation. If the physician, pathology report, or operative note specifies endometrial involvement, C55 is not appropriate and C54.1 must be used.
What documentation is required to support ICD-10 Code C54.1?
The medical record must confirm the endometrium as the primary malignant site, typically through a pathology report or physician attestation. Additional required documentation includes histological type, primary versus secondary status, FIGO stage where known, and the purpose of the encounter (active treatment vs. follow-up), since these determine correct code sequencing.
Which CPT codes are commonly used with C54.1?
Common CPT codes paired with C54.1 include 58558 (hysteroscopy with endometrial biopsy), 58150 (total abdominal hysterectomy), 58571 (laparoscopic hysterectomy), and 58120 (dilation and curettage). E/M codes 99213 to 99215 apply for follow-up and surveillance encounters. Always verify medical necessity pairings against current AMA CPT guidelines and payer local coverage determinations.
What are the most common coding errors for endometrial cancer?
The most common errors are: using C55 when endometrial site is documented; omitting staging codes when the record supports FIGO staging; coding secondary endometrial malignancy as C54.1 instead of C79.x; and using C54.9 (unspecified corpus) when pathology specifies the endometrium. Each of these errors is detectable on audit and can trigger claim denial or request for additional documentation.
