2026 ICD-10-CM Diagnosis Code C7A.091Malignant carcinoid tumor of the thymus

ICD-10-CM Codes›C00–D49›C7A›C7A

ICD-10-CM C7A.091
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

C7A.091 is a billable ICD-10-CM diagnosis code for malignant carcinoid tumor of the thymus. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 826 through 830, 843 through 845. Coders also document this condition as primary malignant neoplasm of thymus. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Malignant neuroendocrine tumors.

Code Identity

ICD-10-CM Code
C7A.091
Billable Status
Yes — Valid for Submission
Code Describes
Malignant carcinoid tumor of the thymus
Short Description
Malignant carcinoid tumor of the thymus
Same as the full description in the CMS dataset.
Parent Code
C7A.09
Malignant carcinoid tumors of other sites

Code Classification

ChapterC00–D49Neoplasms
SectionC7AMalignant neuroendocrine tumors
CategoryC7AMalignant neuroendocrine tumors
This CodeC7A.091Malignant carcinoid tumor of the thymus

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Primary malignant neoplasm of thymus
  • Primary well-differentiated neuroendocrine tumor of thymus
  • Well-differentiated neuroendocrine tumor of thymus

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Tumor
      • carcinoid
        • malignant
          • thymus

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NEO066
Malignant neuroendocrine tumors
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Thymus Cancer

The thymus is a small organ in your upper chest, under your breastbone. Before birth and during childhood, the thymus helps the body make a type of white blood cell. These cells help protect you from infections.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert C7A.091 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
209.22 Malig carcinoid thymus
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About C7A.091Overview

Is C7A.091 (Malignant carcinoid tumors of other sites) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report malignant carcinoid tumor of the thymus on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does C7A.091 group to?

When malignant carcinoid tumor of the thymus is the principal diagnosis on an inpatient stay, it groups to MS-DRG 826, 827, 828, 829, 830, 843, 844, 845, with relative weights from 0.8516 to 4.6778 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of C7A.091?

Under the General Equivalence Mappings, malignant carcinoid tumor of the thymus converts to ICD-9-CM 209.22 (malig carcinoid thymus). The mapping is a direct match.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.