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C7A.1

C7A.1Malignant poorly differentiated neuroendocrine tumors

Billable / specific codeICD-10-CM

C7A.1 is a billable, specific ICD-10-CM code for malignant poorly differentiated neuroendocrine tumors. It is valid for submission on a claim.

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

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

Excludes2 inherited from the categories above C7A.1

Also inherited, and the opposite of Excludes1: these conditions are not part of C7A.1, but a patient can have both, so you may code both.

Written on C7A Malignant neuroendocrine tumors

  • malignant pancreatic islet cell tumors (C25.4)
  • Merkel cell carcinoma (C4A.-)

Other codes that can never be billed with C7A.1

These codes carry an Excludes1 note pointing at C7A.1. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading C7A.1 alone.

  • C75Malignant neoplasm of other endocrine glands and related structures

Risk adjustment

C7A.1 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:

  • HCC 21 Lymphoma and Other Cancers0.671 RAF

Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score.

Medicare coverage

C7A.1 is named in 64 Medicare coverage policies 64 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

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How C7A.1 is indexed

Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to C7A.1.

  • Carcinomaneuroendocrinehigh grade, any site
  • Carcinomaneuroendocrinepoorly differentiated, any site
  • Tumorneuroendocrinemalignant poorly differentiated

Code history

C7A.1 has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.

Related codes at this level

Codes that share C7A. If C7A.1 is not quite right, the correct code is usually one of these.

Questions about C7A.1

Is C7A.1 a billable ICD-10-CM code?
Yes. C7A.1 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does C7A.1 sit in the tabular list?
Neoplasms (C00-D49), in the block Malignant neuroendocrine tumors (C7A).
ICD-10-CMFY2026-Apr· effective April 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release — see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.