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C00.1 ICD-10-CM Code: Malignant neoplasm of external lower lip

Compare with another code for C00.1Check this code on a claim

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives
3 inclusion terms · 3 Excludes1 · 5 use-additional instructions

Billable · FY2027A valid, specific ICD-10-CM code, reportable for dates of service in FY2027.

What you need to know

Source: CMS/NCHS Official ICD-10-CM tabular notes, quoted. From the CMS/NCHS tabular list for the release in force. A note the category or block publishes applies to this code too, and is marked with where it comes from.

Use additional codefrom C00Report with this code when documented
  • Use additional code to identify:
  • alcohol abuse and dependence (F10.-)
  • history of tobacco dependence (Z87.891)
  • tobacco dependence (F17.-)

+1 more in Instructions

Excludes1from C00Not reported with this code unless documented as unrelated
  • malignant melanoma of lip (C43.0)
  • Merkel cell carcinoma of lip (C4A.0)
  • other and unspecified malignant neoplasm of skin of lip (C44.0-)
IncludesWhat this code covers
  • Malignant neoplasm of lower lip NOS
  • Malignant neoplasm of lipstick area of lower lip
  • Malignant neoplasm of vermilion border of lower lip

Where it sits Source: CMS/NCHS

Under:Chapter 2: NeoplasmsC00-C96 Malignant neoplasmsC00-C75 Malignant neoplasms, stated or presumed to be primary (of specified sites), and certain specified histologies, except neuroendocrine, and of lymphoid, hematopoietic and related tissueC00-C14 Malignant neoplasms of lip, oral cavity and pharynxC00 Malignant neoplasm of lip

Most relevant related codes MedCoder-derived

Read off the official notes above and this code’s own position in the tabular list. Which to report is a documentation question; Compare shows the two side by side.

CompareCheck ClaimView Related Codes

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v44, Appendix B.

  • MS-DRG 011 — TRACHEOSTOMY FOR FACE, MOUTH AND NECK DIAGNOSES OR LARYNGECTOMY WITH MCC (MDC PRE)
  • MS-DRG 012 — TRACHEOSTOMY FOR FACE, MOUTH AND NECK DIAGNOSES OR LARYNGECTOMY WITH CC (MDC PRE)
  • MS-DRG 013 — TRACHEOSTOMY FOR FACE, MOUTH AND NECK DIAGNOSES OR LARYNGECTOMY WITHOUT CC/MCC (MDC PRE)
  • MS-DRG 146 — EAR, NOSE, MOUTH AND THROAT MALIGNANCY WITH MCC (MDC 03)
  • MS-DRG 147 — EAR, NOSE, MOUTH AND THROAT MALIGNANCY WITH CC (MDC 03)
  • MS-DRG 148 — EAR, NOSE, MOUTH AND THROAT MALIGNANCY WITHOUT CC/MCC (MDC 03)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for C00.1 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2027Effective: October 1, 2026

Trace:FY2027 changesChange historyRelease, file and checksum

Notes without a marker are published on C00.1 itself; “inherited from” names the category or block whose note applies here.

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Malignant neoplasm of lower lip NOS
  • Malignant neoplasm of lipstick area of lower lip
  • Malignant neoplasm of vermilion border of lower lip

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Source: inherited from C00

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional code to identify:
  • alcohol abuse and dependence (F10.-)
  • history of tobacco dependence (Z87.891)
  • tobacco dependence (F17.-)
  • tobacco use (Z72.0)

Source: inherited from C00

Coder workflow for C00.1

MedCoder structured workflow — derived from this code’s own official record

Before you code C00.1

  1. Confirm the documented site and behavior (this code’s block classifies malignant neoplasms), whether the site is primary or secondary, and whether the malignancy is current or a personal history: a previously excised malignancy with no further treatment and no evidence of disease is history, not current disease. Verify the site against the Table of Neoplasms. Neoplasm chapter guidelines (Guidelines I.C.2.a, I.C.2.d, I.C.2.m).

    See the Table of Neoplasms entries · Guide: Active cancer vs history of cancer →

  2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with C00.1. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

    See the official tabular notes

Choose the right path

  1. Does the documentation support a condition named in C00.1’s Excludes1 note?
    Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
    No → Continue.

    ReviewC43.0, C4A.0, C44.0

Consider C00.1. Then work the Use Additional Code note, and confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).
Anatomical site
At the most specific level the record states; a site the classification separates cannot be assumed from a procedure or a measurement.
The conditions the Use Additional Code note names
Reported with this code when documented; a conditional instruction (“if applicable”, “if known”) applies only when the record supports it.
Behavior and current-versus-history status
Malignant, in situ, benign or uncertain; primary or secondary; current disease or personal history (Guidelines I.C.2.m).

Official instructions as workflow

  • Excludes1 — check before selecting C00.1(3 notes)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with C00.1: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareC43.0, C4A.0, C44.0

    See the official tabular notes · Guidelines I.A.12.a

  • Use Additional Code — after identifying C00.1(5 notes)

    Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with C00.1 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

    ReviewF10, Z87.891, F17, Z72.0

    See the official tabular notes · Guidelines I.A.13

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: Both the condition C00.1 describes and a condition named in its Excludes1 note are documented for the same encounter.

Coding question: Can both codes be reported?

Path: Review the Excludes1 note and the excluded code, and look for a provider statement on whether the two conditions are related.

Reason: Excludes1 means the two are not coded together; the exception is when the record shows the conditions are unrelated to each other (Guidelines I.A.12.a).

ReviewC43.0, C4A.0, C44.0

Documentation: A condition the Use Additional Code note names is documented.

Coding question: Is a second code reported with C00.1?

Path: Review the Use Additional Code note and the code it names.

Reason: The additional code is reported when the record documents the condition; a conditional instruction applies only when its condition is met (Guidelines I.A.13).

ReviewF10, Z87.891, F17, Z72.0

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Don’t confuse C00.1 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of C00.1 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

  • C43.0— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of malignant melanoma of lip moves the case to C43.0; the two are not reported together unless documented as unrelated.

    Full comparison: C00.1 vs C43.0 →

  • C4A.0— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of Merkel cell carcinoma of lip moves the case to C4A.0; the two are not reported together unless documented as unrelated.

    Full comparison: C00.1 vs C4A.0 →

  • C44.0— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of other and unspecified malignant neoplasm of skin of lip moves the case to C44.0; the two are not reported together unless documented as unrelated.

    Full comparison: C00.1 vs C44.0 →

  • C00.2— Specificity relationship (Review)

    Overlapping diagnoses in the same category.

    Overlapping codes in the same category — the documentation decides which is the more specific fit.

    What moves you there: A record that documents no more than “Malignant neoplasm of external lip, unspecified” takes C00.2; specificity in the record moves it back here.

    Full comparison: C00.1 vs C00.2 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Coding context

Guidelines, coding notes, decision aids, relationships (with MS-DRG and CCSR classification), hierarchy, HCC, coverage and the context map: what a coder reaches for after the core. Each section names whether it is official source data, a MedCoder-derived relationship or MedCoder editorial.

Code Overview

Malignant neoplasm of external lower lip is a billable ICD-10-CM diagnosis code (C00.1).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Verify Before Coding

  • No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder-derived relationships — computed from published CMS and AHRQ datasets

Other codes that name C00.1 or its code family, from the CMS ICD-10-CM tabular instructional notes, the CMS Table of Neoplasms and the CMS Table of Neoplasms (site match derived from the code title). Tabular-note edges are stored at the code family level that carries each note.

Referenced by 3 Excludes1 notes: C43.0 — Malignant melanoma of lip, C44.0 — Other and unspecified malignant neoplasm of skin of lip (via C00.-), C4A.0 — Merkel cell carcinoma of lip.

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 5 Same-site neoplasm codes: C79.89 — Secondary malignant neoplasm of other specified sitesCompare C00.1 vs C79.89 →, D00.01 — Carcinoma in situ of labial mucosa and vermilion borderCompare C00.1 vs D00.01 →, D10.0 — Benign neoplasm of lipCompare C00.1 vs D10.0 →, D37.01 — Neoplasm of uncertain behavior of lipCompare C00.1 vs D37.01 →, D49.0 — Neoplasm of unspecified behavior of digestive systemCompare C00.1 vs D49.0 →.

These codes represent related neoplasm behaviors affecting the same anatomic site.

Referenced by 3 Screening & history codes: Z85.81 — Personal history of malignant neoplasm of lip, oral cavity, and pharynxCompare C00.1 vs Z85.81 →, Z85.818 — Personal history of malignant neoplasm of other sites of lip, oral cavity, and pharynxCompare C00.1 vs Z85.818 →, Z85.819 — Personal history of malignant neoplasm of unspecified site of lip, oral cavity, and pharynxCompare C00.1 vs Z85.819 →.

These codes represent screening tests and history codes that refer to this active disease condition.

MS-DRG Grouper Relationships (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 MS-DRG: not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity for that release.

Named in the grouper logic of 6 MS-DRGs: DRG 011 (MDC PRE), DRG 012 (MDC PRE), DRG 013 (MDC PRE), DRG 146 (MDC 03), DRG 147 (MDC 03), DRG 148 (MDC 03).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):NEO002 — Head and neck cancers - lip and oral cavity (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Head and neck cancers - lip and oral cavity).

C00.0 — Malignant neoplasm of external upper lip, C00.2 — Malignant neoplasm of external lip, unspecified, C00.3 — Malignant neoplasm of upper lip, inner aspect, C00.4 — Malignant neoplasm of lower lip, inner aspect, C00.5 — Malignant neoplasm of lip, unspecified, inner aspect, C00.6 — Malignant neoplasm of commissure of lip, unspecified, C00.8 — Malignant neoplasm of overlapping sites of lip, C00.9 — Malignant neoplasm of lip, unspecified, C01 — Malignant neoplasm of base of tongue, C02.0 — Malignant neoplasm of dorsal surface of tongue, C02.1 — Malignant neoplasm of border of tongue, C02.2 — Malignant neoplasm of ventral surface of tongue, C02.3 — Malignant neoplasm of anterior two-thirds of tongue, part unspecified, C02.4 — Malignant neoplasm of lingual tonsil, C02.8 — Malignant neoplasm of overlapping sites of tongue, C02.9 — Malignant neoplasm of tongue, unspecified, C03.0 — Malignant neoplasm of upper gum, C03.1 — Malignant neoplasm of lower gum, C03.9 — Malignant neoplasm of gum, unspecified, C04.0 — Malignant neoplasm of anterior floor of mouth, +22 more

Lab tests where this diagnosis supports Medicare coverage (NCD)

Medicare's National Coverage Determination (NCD) program lists this diagnosis as medical justification for these lab tests.

Iron Panel

Contextual Map

Every relationship of C00.1 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run C00.1 with these 3 related codes in Claim Check

Hierarchy

Same site

Referenced by Excludes1 notes

Referenced by Same-site neoplasm codes

Referenced by Screening & history codes MedCoder-derived

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • Pre-MDC[MDC crossing]: “Pre-MDC — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 175 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2027
  • MDC 03 — Diseases and Disorders of the Ear, Nose, Mouth and Throat[MDC crossing]: “Diseases and Disorders of the Ear, Nose, Mouth and Throat — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 5,151 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2027

Neoplasm sites

  • Neoplasm, neoplastic, lip, external, lower — Neoplasm, neoplastic, lip, external, lower — Malignant, Primary [Neoplasm table]: “Neoplasm, neoplastic, lip, external, lower (Malignant, Primary)”— CMS Table of Neoplasms · icd10cm-fy2027
  • Neoplasm, neoplastic, lip, lipstick area, lower — Neoplasm, neoplastic, lip, lipstick area, lower — Malignant, Primary [Neoplasm table]: “Neoplasm, neoplastic, lip, lipstick area, lower (Malignant, Primary)”— CMS Table of Neoplasms · icd10cm-fy2027
  • Neoplasm, neoplastic, lip, lower — Neoplasm, neoplastic, lip, lower — Malignant, Primary [Neoplasm table]: “Neoplasm, neoplastic, lip, lower (Malignant, Primary)”— CMS Table of Neoplasms · icd10cm-fy2027
  • Neoplasm, neoplastic, lip, vermilion border, lower — Neoplasm, neoplastic, lip, vermilion border, lower — Malignant, Primary [Neoplasm table]: “Neoplasm, neoplastic, lip, vermilion border, lower (Malignant, Primary)”— CMS Table of Neoplasms · icd10cm-fy2027

Nearest codes (9)

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Reference

Index terms and tables, published questions and FAQ, every source behind this page with its release and checksum, the date-of-service check and the complete change history.

Neoplasm Table Sites (4)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Anatomical sites from the official ICD-10-CM Table of Neoplasms that map to this code, with the matching behavior column.

  • Neoplasm, neoplastic, lip, external, lower — Malignant, Primary
  • Neoplasm, neoplastic, lip, lipstick area, lower — Malignant, Primary
  • Neoplasm, neoplastic, lip, lower — Malignant, Primary
  • Neoplasm, neoplastic, lip, vermilion border, lower — Malignant, Primary

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2027 tabular list, index and tables, effective October 1, 2026 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v44.0 (October 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v44 Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder-derived relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder editorial explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 28, 2026 · All releases and sources

Labels on this page: Official source data · MedCoder-derived relationship · MedCoder editorial explanation. How to read the labels · All data sources and release dates · CMS coding rules

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "C00.1 — Malignant neoplasm of external lower lip." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/c00.1-malignant-neoplasm-of-external-lower-lip

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Malignant neoplasm of external lower lip

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027, and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to C00.1 in its code family, with their registry titles.

View all codes in the C00 family