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C7A.091 ICD-10-CM Code: Malignant carcinoid tumor of the thymus

Compare with another codeCheck 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
2 Excludes2 · 2 use-additional codes · 1 code-also instruction
Risk adjustment
CMS-HCC V28: 1 category · CMS-HCC V22 category 12 · RxHCC V08 category 22

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; the Instructions section marks which is which.

Use additional codeReport with this code when documented
  • code to identify any associated endocrine syndrome, such as:
  • carcinoid syndrome (E34.00)
Code alsoMay be needed with this code
  • any associated multiple endocrine neoplasia [MEN] syndromes (E31.2-)
Excludes2Not included here; may be reported together
  • malignant pancreatic islet cell tumors (C25.4)
  • Merkel cell carcinoma (C4A.-)

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 826 — MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASMS WITH MAJOR O.R. PROCEDURES WITH MCC (MDC 17)
  • MS-DRG 827 — MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASMS WITH MAJOR O.R. PROCEDURES WITH CC (MDC 17)
  • MS-DRG 828 — MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASMS WITH MAJOR O.R. PROCEDURES WITHOUT CC/MCC (MDC 17)
  • MS-DRG 829 — MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASMS WITH OTHER PROCEDURES WITH CC/MCC (MDC 17)
  • MS-DRG 830 — MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASMS WITH OTHER PROCEDURES WITHOUT CC/MCC (MDC 17)
  • MS-DRG 843 — OTHER MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASTIC DIAGNOSES WITH MCC (MDC 17)
  • MS-DRG 844 — OTHER MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASTIC DIAGNOSES WITH CC (MDC 17)
  • MS-DRG 845 — OTHER MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASTIC DIAGNOSES WITHOUT CC/MCC (MDC 17)

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 12 · RxHCC V08 HCC 22

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 C7A.091 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 C7A.091 itself; “inherited from” names the category or block whose note applies here.

Excludes2 — Not Included Here

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

Source: inherited from C7A

Code Also

Additional codes that may be required to fully describe the encounter.

  • any associated multiple endocrine neoplasia [MEN] syndromes (E31.2-)

Source: inherited from C7A

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional code to identify any associated endocrine syndrome, such as:
  • carcinoid syndrome (E34.00)

Source: inherited from C7A

Coder workflow for C7A.091

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

Before you code C7A.091

  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 →

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

  • Excludes2 — not part of C7A.091(2 notes)

    Coding workflow: The conditions named in this note are not included in C7A.091. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareC25.4, C4A

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

  • Use Additional Code — after identifying C7A.091(2 notes)

    Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with C7A.091 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

    ReviewE34.00

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

  • Code Also — related condition(1 note)

    Coding workflow: Review the related condition when both are documented and the instruction applies. A Code Also note does not fix sequencing; the order follows the circumstances of the encounter.

    ReviewE31.2

    See the official tabular notes · Guidelines I.A.17

Coding decision scenarios

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

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

Coding question: Is a second code reported with C7A.091?

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).

ReviewE34.00

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 C7A.091 with…

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

The codes most likely to be picked instead of C7A.091 — 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.

  • C7A.094— 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 carcinoid tumor of the foregut, unspecified” takes C7A.094; specificity in the record moves it back here.

    Full comparison: C7A.091 vs C7A.094 →

  • C25.4— 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 pancreatic islet cell tumors adds C25.4; it is not part of this code and both may be reported when both are documented.

    Full comparison: C7A.091 vs C25.4 →

  • C4A— 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 Merkel cell carcinoma adds C4A; it is not part of this code and both may be reported when both are documented.

    Full comparison: C7A.091 vs C4A →

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 carcinoid tumor of the thymus is a billable ICD-10-CM diagnosis code (C7A.091).

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

Decision Points

The directives on this code's own record, as a pre-claim checklist.

  1. 2 Use Additional Code instructions — report the named additional code(s) when the documentation supports them. See the Use Additional Code notes
  2. 1 Code Also note — a second code may apply; the guidelines leave its sequencing to the circumstances of the encounter. See the Code Also notes
  3. 2 Excludes2 entries — those conditions are not part of this code and may be reported additionally when documented. See the Excludes2 notes

Checklist rows are derived from this code's own official directives; the wording of each check is MedCoder editorial. The official notes themselves are in the sections each row links to.

Verify Before Coding

  • CC as a secondary diagnosis (FY2027). Can raise the stay's MS-DRG severity tier.

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 C7A.091 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 3 Excludes1 notes: C37 — Malignant neoplasm of thymus, C75 — Malignant neoplasm of other endocrine glands and related structures (via C7A.-), C75 — Malignant neoplasm of other endocrine glands and related structures (via C7A.0.-).

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

Referenced by 1 Code Also instruction: E34.0 — Carcinoid syndrome (via C7A.-).

These codes suggest coding this condition alongside when both are present.

MS-DRG Grouper Relationships (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 MS-DRG: CC — Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 24 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 8 MS-DRGs: DRG 826 (MDC 17), DRG 827 (MDC 17), DRG 828 (MDC 17), DRG 829 (MDC 17), DRG 830 (MDC 17), DRG 843 (MDC 17), DRG 844 (MDC 17), DRG 845 (MDC 17).

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

Clinical classification (AHRQ CCSR):NEO066 — Malignant neuroendocrine tumors (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 process (MS-DRG)

Acts as CC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

C7A.011 — Malignant carcinoid tumor of the jejunum, C7A.012 — Malignant carcinoid tumor of the ileum, C7A.019 — Malignant carcinoid tumor of the small intestine, unspecified portion, C7A.020 — Malignant carcinoid tumor of the appendix, C7A.021 — Malignant carcinoid tumor of the cecum, C7A.022 — Malignant carcinoid tumor of the ascending colon, C7A.023 — Malignant carcinoid tumor of the transverse colon, C7A.024 — Malignant carcinoid tumor of the descending colon, C7A.025 — Malignant carcinoid tumor of the sigmoid colon, C7A.026 — Malignant carcinoid tumor of the rectum, C7A.029 — Malignant carcinoid tumor of the large intestine, unspecified portion, C7A.090 — Malignant carcinoid tumor of the bronchus and lung, C7A.092 — Malignant carcinoid tumor of the stomach, C7A.093 — Malignant carcinoid tumor of the kidney, C7A.094 — Malignant carcinoid tumor of the foregut, unspecified, C7A.095 — Malignant carcinoid tumor of the midgut, unspecified, C7A.096 — Malignant carcinoid tumor of the hindgut, unspecified, C7A.098 — Malignant carcinoid tumors of other sites, C7A.1 — Malignant poorly differentiated neuroendocrine tumors, C7A.8 — Other malignant neuroendocrine tumors, +3 more

Same CMS-HCC risk category (V28)

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

C7A.019 — Malignant carcinoid tumor of the small intestine, unspecified portion, C7A.020 — Malignant carcinoid tumor of the appendix, C7A.021 — Malignant carcinoid tumor of the cecum, C7A.022 — Malignant carcinoid tumor of the ascending colon, C7A.023 — Malignant carcinoid tumor of the transverse colon, C7A.024 — Malignant carcinoid tumor of the descending colon, C7A.025 — Malignant carcinoid tumor of the sigmoid colon, C7A.026 — Malignant carcinoid tumor of the rectum, C7A.029 — Malignant carcinoid tumor of the large intestine, unspecified portion, C7A.090 — Malignant carcinoid tumor of the bronchus and lung, C7A.092 — Malignant carcinoid tumor of the stomach, C7A.093 — Malignant carcinoid tumor of the kidney, C7A.094 — Malignant carcinoid tumor of the foregut, unspecified, C7A.095 — Malignant carcinoid tumor of the midgut, unspecified, C7A.096 — Malignant carcinoid tumor of the hindgut, unspecified, C7A.098 — Malignant carcinoid tumors of other sites, C7A.1 — Malignant poorly differentiated neuroendocrine tumors, C7A.8 — Other malignant neuroendocrine tumors, C81.00 — Nodular lymphocyte predominant Hodgkin lymphoma, unspecified site, C81.01 — Nodular lymphocyte predominant Hodgkin lymphoma, lymph nodes of head, face, and neck, +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 (Malignant neuroendocrine tumors).

C7A.019 — Malignant carcinoid tumor of the small intestine, unspecified portion, C7A.020 — Malignant carcinoid tumor of the appendix, C7A.021 — Malignant carcinoid tumor of the cecum, C7A.022 — Malignant carcinoid tumor of the ascending colon, C7A.023 — Malignant carcinoid tumor of the transverse colon, C7A.024 — Malignant carcinoid tumor of the descending colon, C7A.025 — Malignant carcinoid tumor of the sigmoid colon, C7A.026 — Malignant carcinoid tumor of the rectum, C7A.029 — Malignant carcinoid tumor of the large intestine, unspecified portion, C7A.090 — Malignant carcinoid tumor of the bronchus and lung, C7A.092 — Malignant carcinoid tumor of the stomach, C7A.093 — Malignant carcinoid tumor of the kidney, C7A.094 — Malignant carcinoid tumor of the foregut, unspecified, C7A.095 — Malignant carcinoid tumor of the midgut, unspecified, C7A.096 — Malignant carcinoid tumor of the hindgut, unspecified, C7A.098 — Malignant carcinoid tumors of other sites, C7A.1 — Malignant poorly differentiated neuroendocrine tumors, C7A.8 — Other malignant neuroendocrine tumors, C7B.00 — Secondary carcinoid tumors, unspecified site, C7B.01 — Secondary carcinoid tumors of distant lymph nodes, +10 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Tumor”; these codes share that main term but sit in a different category of the Tabular List.

C56 — Malignant neoplasm of ovary (Brenner, malignant), C56.9 — Malignant neoplasm of unspecified ovary (yolk sac, unspecified site, female), C62.90 — Malignant neoplasm of unspecified testis, unspecified whether descended or undescended (yolk sac, unspecified site, male), C64 — Malignant neoplasm of kidney, except renal pelvis (Wilms'), C71.9 — Malignant neoplasm of brain, unspecified (neuroectodermal, primitive, unspecified site), C73 — Malignant neoplasm of thyroid gland (Hurthle cell, malignant), C74.0 — Malignant neoplasm of cortex of adrenal gland (adrenal, cortical, malignant), C75.4 — Malignant neoplasm of carotid body (carotid body, malignant), C75.5 — Malignant neoplasm of aortic body and other paraganglia (aortic body, malignant), C79.6 — Secondary malignant neoplasm of ovary (Krukenberg's), C7B.00 — Secondary carcinoid tumors, unspecified site (secondary, carcinoid), C7B.01 — Secondary carcinoid tumors of distant lymph nodes (carcinoid, secondary, distant lymph nodes), C7B.02 — Secondary carcinoid tumors of liver (carcinoid, secondary, liver), C7B.03 — Secondary carcinoid tumors of bone (secondary, carcinoid, bone), C7B.04 — Secondary carcinoid tumors of peritoneum (carcinoid, mesentery metastasis), C7B.09 — Secondary carcinoid tumors of other sites (secondary, carcinoid, specified NEC), C7B.8 — Other secondary neuroendocrine tumors (neuroendocrine, secondary NEC), C80.1 — Malignant (primary) neoplasm, unspecified (malignant), D13.7 — Benign neoplasm of endocrine pancreas (beta-cell, pancreas), D18.00 — Hemangioma unspecified site (glomus), +75 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.

Alpha-Fetoprotein (AFP) Test, CEA Test, Gamma-glutamyl Transferase (GGT) Test, Iron Panel, Prothrombin Time Test and INR (PT/INR)

Contextual Map

Every relationship of C7A.091 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 C7A.091 with these 3 related codes in Claim Check

Hierarchy

Referenced by Excludes1 notes

Referenced by Code Also instructions

  • E34.0 — Carcinoid syndrome[Code Also](via C7A.-): “primary neuroendocrine tumors (C7A.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2027

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

  • MDC 17 — Myeloproliferative Diseases and Disorders, Poorly Differentiated Neoplasms[MDC crossing]: “Myeloproliferative Diseases and Disorders, Poorly Differentiated Neoplasms — 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. 4,735 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2027

Index entries

  • Tumor, carcinoid, malignant, thymus[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027

Nearest codes (27)

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.

Indexed Clinical Terms (1)

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

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

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-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. "C7A.091 — Malignant carcinoid tumor of the thymus." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/c7a.091-malignant-carcinoid-tumor-of-the-thymus

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Malignant carcinoid tumor of the thymus

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 C7A.091 in its code family, with their registry titles.

View all codes in the C7A family