2026 ICD-10-CM Diagnosis Code C7A.1Malignant poorly differentiated neuroendocrine tumors

ICD-10-CM Codes›C00–D49›C7A›C7A

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

C7A.1 is a billable ICD-10-CM diagnosis code for malignant poorly differentiated neuroendocrine tumors. 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Malignant neuroendocrine tumors.

Code Identity

ICD-10-CM Code
C7A.1
Billable Status
Yes — Valid for Submission
Code Describes
Malignant poorly differentiated neuroendocrine tumors
Short Description
Malignant poorly differentiated neuroendocrine tumors
Same as the full description in the CMS dataset.
Parent Code
C7A
Malignant neuroendocrine tumors

Code Classification

ChapterC00–D49Neoplasms
SectionC7AMalignant neuroendocrine tumors
CategoryC7AMalignant neuroendocrine tumors
This CodeC7A.1Malignant poorly differentiated neuroendocrine tumors

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Malignant poorly differentiated neuroendocrine tumor NOS
  • Malignant poorly differentiated neuroendocrine carcinoma, any site
  • High grade neuroendocrine carcinoma, any site

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.

    • Carcinoma(malignant)
      • neuroendocrine
        • high grade, any site
    • Carcinoma(malignant)
      • neuroendocrine
        • poorly differentiated, any site
    • Tumor
      • neuroendocrine
        • malignant poorly differentiated

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

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Read the full article at MedlinePlus

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Convert C7A.1 to ICD-9-CMHistory

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

ICD-9-CM
209.30 Malig neuroendo ca NOS
Approximate The match is approximate rather than exact.

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.1Overview

Is C7A.1 (Malignant neuroendocrine tumors) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report malignant poorly differentiated neuroendocrine tumors on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does C7A.1 group to?

When malignant poorly differentiated neuroendocrine tumors 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.1?

Under the General Equivalence Mappings, malignant poorly differentiated neuroendocrine tumors converts to ICD-9-CM 209.30 (malig neuroendo ca NOS). The mapping is approximate, so confirm the match fits the documentation.

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.