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C09.9 ICD-10-CM Code: Malignant neoplasm of tonsil, unspecified

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

Coding at a Glance

Tabular directives
3 inclusion terms · 2 Excludes2 · 8 use-additional codes
Risk adjustment
CMS-HCC V28: 1 category · CMS-HCC V22 category 11

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.

Risk Adjustment (CMS-HCC)

Payment categories this diagnosis maps to under CMS-HCC V28, payment year 2026.

  • HCC 21 — Lymphoma and Other Cancers (supersedes HCC 22, HCC 23)

Other models: CMS-HCC V22 HCC 11

Risk scores depend on the enrollee's full accepted diagnosis set and segment; a category mapping alone does not determine payment.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for C09.9 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 C09.9 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 tonsil NOS
  • Malignant neoplasm of faucial tonsils
  • Malignant neoplasm of palatine tonsils

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Source: inherited from C09

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional code to identify:
  • alcohol abuse and dependence (F10.-)
  • exposure to environmental tobacco smoke (Z77.22)
  • exposure to tobacco smoke in the perinatal period (P96.81)
  • history of tobacco dependence (Z87.891)
  • occupational exposure to environmental tobacco smoke (Z57.31)
  • tobacco dependence (F17.-)
  • tobacco use (Z72.0)

Source: inherited from C09

Coder workflow for C09.9

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

Before you code C09.9

  1. Unspecified does not mean incorrect. When the record gives no greater specificity, C09.9 may be the appropriate code. Check the record for detail that supports a more specific sibling. An unspecified code is for records that do not provide the detail a more specific code needs; a query, not an assumption, is the route to specificity (Guidelines I.A.9.b, I.B.18).

    ReviewC09.0, C09.1, C09.8

    See the relationships section · Guide: Other vs unspecified (NEC vs NOS) →

  2. 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 →

Choose the right path

  1. Does the record document the detail a more specific sibling code needs?
    Yes → Review the specific siblings in this subcategory.
    No → Continue — C09.9 is appropriate when the documentation goes no further.

    ReviewC09.0, C09.1, C09.8

Consider C09.9. 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).
Any detail beyond this code’s title
What the record states that a more specific sibling code would capture — or its absence, which itself supports the unspecified code.

Official instructions as workflow

  • Excludes2 — not part of C09.9(2 notes)

    Coding workflow: The conditions named in this note are not included in C09.9. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareC02.4, C11.1

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

  • Use Additional Code — after identifying C09.9(8 notes)

    Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with C09.9 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

    ReviewF10, Z77.22, P96.81, Z87.891, Z57.31, F17

    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: The provider documents the condition in the terms of this code’s title and records no further detail.

Coding question: Is a more specific sibling code supportable?

Path: Review the specific siblings in this subcategory and what each requires the record to state.

Reason: A more specific code needs documentation of the distinguishing element; without it the unspecified code is appropriate, and a provider query is the route to specificity (Guidelines I.A.9.b, I.B.18).

ReviewC09.0, C09.1, C09.8

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

Coding question: Is a second code reported with C09.9?

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, Z77.22, P96.81, Z87.891, Z57.31, F17

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.

Coding context

The comparisons, hierarchy, index entries, guidelines, relationships, risk-adjustment and coverage context a coder commonly needs. Each section names whether it is official source data, a MedCoder-derived relationship or MedCoder editorial.

Don’t confuse C09.9 with…

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

The codes most likely to be picked instead of C09.9 — 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.

  • C02.4— Excludes2 relationship (Informational)

    Distinct conditions — both may be reported.

    A distinct condition — both may be reported when both are documented.

    What moves you there: Documentation of malignant neoplasm of lingual tonsil adds C02.4; it is not part of this code and both may be reported when both are documented.

    Full comparison: C09.9 vs C02.4 →

  • C11.1— Excludes2 relationship (Informational)

    Distinct conditions — both may be reported.

    A distinct condition — both may be reported when both are documented.

    What moves you there: Documentation of malignant neoplasm of pharyngeal tonsil adds C11.1; it is not part of this code and both may be reported when both are documented.

    Full comparison: C09.9 vs C11.1 →

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.

Code Overview

Malignant neoplasm of tonsil, unspecified is a billable ICD-10-CM diagnosis code (C09.9).

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

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, fauces, faucial NEC, tonsil — Malignant, Primary
  • Neoplasm, neoplastic, tonsil — Malignant, Primary
  • Neoplasm, neoplastic, tonsil, fauces, faucial — Malignant, Primary
  • Neoplasm, neoplastic, tonsil, palatine — Malignant, Primary

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 structured relationships — computed from published CMS and AHRQ datasets

Other codes that name C09.9 or its code family, from the CMS ICD-10-CM tabular instructional notes and the CMS Table of Neoplasms. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 2 Excludes2 notes: C02.4 — Malignant neoplasm of lingual tonsil, C10 — Malignant neoplasm of oropharynx (via C09.-).

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

Referenced by 5 Same-site neoplasm codes: C79.89 — Secondary malignant neoplasm of other specified sitesCompare C09.9 vs C79.89 →, D00.08 — Carcinoma in situ of pharynxCompare C09.9 vs D00.08 →, D10.4 — Benign neoplasm of tonsilCompare C09.9 vs D10.4 →, D37.05 — Neoplasm of uncertain behavior of pharynxCompare C09.9 vs D37.05 →, D49.0 — Neoplasm of unspecified behavior of digestive systemCompare C09.9 vs D49.0 →.

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

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):NEO009 — Head and neck cancers - tonsils (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 CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Lymphoma and Other Cancers) for risk-adjusted payment.

C06.80 — Malignant neoplasm of overlapping sites of unspecified parts of mouth, C06.89 — Malignant neoplasm of overlapping sites of other parts of mouth, C06.9 — Malignant neoplasm of mouth, unspecified, C07 — Malignant neoplasm of parotid gland, C08.0 — Malignant neoplasm of submandibular gland, C08.1 — Malignant neoplasm of sublingual gland, C08.9 — Malignant neoplasm of major salivary gland, unspecified, C09.0 — Malignant neoplasm of tonsillar fossa, C09.1 — Malignant neoplasm of tonsillar pillar (anterior) (posterior), C09.8 — Malignant neoplasm of overlapping sites of tonsil, C10.0 — Malignant neoplasm of vallecula, C10.1 — Malignant neoplasm of anterior surface of epiglottis, C10.2 — Malignant neoplasm of lateral wall of oropharynx, C10.3 — Malignant neoplasm of posterior wall of oropharynx, C10.4 — Malignant neoplasm of branchial cleft, C10.8 — Malignant neoplasm of overlapping sites of oropharynx, C10.9 — Malignant neoplasm of oropharynx, unspecified, C11.0 — Malignant neoplasm of superior wall of nasopharynx, C11.1 — Malignant neoplasm of posterior wall of nasopharynx, C11.2 — Malignant neoplasm of lateral wall of nasopharynx, +442 more

Related risk categories

These categories interact through CMS's HCC hierarchy — one can suppress the other's risk-adjustment weight when both are present on a claim.

Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic, Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers, Lung and Other Severe Cancers, Bladder, Colorectal, and Other Cancers, Prostate, Breast, and Other Cancers and Tumors

Same clinical category (CCSR)

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

C09.0 — Malignant neoplasm of tonsillar fossa, C09.1 — Malignant neoplasm of tonsillar pillar (anterior) (posterior), C09.8 — Malignant neoplasm of overlapping sites of tonsil

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 C09.9 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 C09.9 with these 2 related codes in Claim Check

Hierarchy

Same site

Referenced by Excludes2 notes

Referenced by Same-site neoplasm codes

Clinical classification (CCSR)

Risk adjustment (CMS-HCC)

  • HCC 21 — Lymphoma and Other Cancers [CMS-HCC]: “Lymphoma and Other Cancers — supersedes HCC 22 (Bladder, Colorectal, and Other Cancers), HCC 23 (Prostate, Breast, and Other Cancers and Tumors)”— CMS-HCC V28 · 2026

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, fauces, faucial NEC, tonsil — Neoplasm, neoplastic, fauces, faucial NEC, tonsil — Malignant, Primary [Neoplasm table]: “Neoplasm, neoplastic, fauces, faucial NEC, tonsil (Malignant, Primary)”— CMS Table of Neoplasms · icd10cm-fy2027
  • Neoplasm, neoplastic, tonsil — Neoplasm, neoplastic, tonsil — Malignant, Primary [Neoplasm table]: “Neoplasm, neoplastic, tonsil (Malignant, Primary)”— CMS Table of Neoplasms · icd10cm-fy2027
  • Neoplasm, neoplastic, tonsil, fauces, faucial — Neoplasm, neoplastic, tonsil, fauces, faucial — Malignant, Primary [Neoplasm table]: “Neoplasm, neoplastic, tonsil, fauces, faucial (Malignant, Primary)”— CMS Table of Neoplasms · icd10cm-fy2027
  • Neoplasm, neoplastic, tonsil, palatine — Neoplasm, neoplastic, tonsil, palatine — Malignant, Primary [Neoplasm table]: “Neoplasm, neoplastic, tonsil, palatine (Malignant, Primary)”— CMS Table of Neoplasms · icd10cm-fy2027

Nearest codes

Change history

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

Deep reference

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

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
Risk adjustment Official source data
2026 Mid-Year Final ICD-10 Mappings + Model Software (cms.gov/files/zip/2026-midyear-final-icd-10-mappings.zip, 2026-midyear-final-model-software.zip) — CMS-HCC V28, PY2026 mid-year final release 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 structured 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 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 20, 2026 · All releases and sources

Labels on this page: Official source data · MedCoder structured relationship · MedCoder 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. "C09.9 — Malignant neoplasm of tonsil, unspecified." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/c09.9-malignant-neoplasm-of-tonsil-unspecified

Change history

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

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 C09.9 in its code family, with their registry titles.

View all codes in the C09 family