2027 ICD-10-CM Diagnosis Code C7B.8Other secondary neuroendocrine tumors

ICD-10-CM Codes›C00–D49›C7B›C7B

ICD-10-CM C7B.8
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

C7B.8 is a billable ICD-10-CM diagnosis code for other secondary neuroendocrine tumors. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 826 through 830, 843 through 845. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 23 closely related codes. Coders also document this condition as carcinoma of peritoneum. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Malignant neuroendocrine tumors.

For Medicare Advantage risk adjustment, C7B.8 maps to CMS-HCC Category 17 (Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic) under the V28 model, adding a risk factor of about 4.209 for a community, non-dual, aged beneficiary in payment year 2027.

Code Identity

ICD-10-CM Code
C7B.8
Billable Status
Yes — Valid for Submission
Code Describes
Other secondary neuroendocrine tumors
Short Description
Other secondary neuroendocrine tumors
Same as the full description in the CMS dataset.
Parent Code
C7B
Secondary neuroendocrine tumors

Code Classification

ChapterC00–D49Neoplasms
SectionC7BSecondary neuroendocrine tumors
CategoryC7BSecondary neuroendocrine tumors
This CodeC7B.8Other secondary neuroendocrine tumors

Medicare Risk Adjustment (HCC)Billing

C7B.8 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.

CMS-HCC V28 Category (Payment Model)
HCC 17— Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic
Payment HCC · PY 2027 one of 78 ICD-10-CM codes in this category
Risk Adjustment Factor (RAF) Weight
+4.209
community, non-dual, aged · ranges 1.952–4.235 across segments
Hierarchy
Supersedes HCC 18, HCC 19, HCC 20, HCC 21, HCC 22, and HCC 23
less severe related categories are not paid alongside HCC 17
Prior Model (CMS-HCC V24)
HCC 8
V24 retired V28 pays 100% of MA risk scores since PY 2026
Other CMS Models
PACE (CMS-HCC V22): HCC 8 · ESRD (V21): HCC 8 · ESRD (V24): HCC 8
ESRD V21 weights: 0.295 dialysis, 1.289–2.627 functioning graft · ESRD V24 weights: 0.353 dialysis, 1.571–3.226 functioning graft
Part D (RxHCC)
RxHCC 18 — Secondary Cancer of Lung, Liver, Brain, and Other Sites
also risk-adjusts in the Part D prescription drug model (V08)

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Carcinoma of peritoneum
  • Metastatic neuroendocrine carcinoma to peritoneum

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to C7B.8: its own notes plus those printed at C7B and Chapter 2. A note printed at a category, block or chapter applies to every code under it.

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From C7B Secondary neuroendocrine tumors applies to 8 codes
  • code to identify any functional activity

Notes

General instructions on how these codes are used.

From Chapter 2 (C00-D49) Neoplasms applies to 1,730 codes
  • Functional activity
  • All neoplasms are classified in this chapter, whether they are functionally active or not. An additional code from Chapter 4 may be used, to identify functional activity associated with any neoplasm.
  • Morphology [Histology]
  • Chapter 2 classifies neoplasms primarily by site (topography), with broad groupings for behavior, malignant, in situ, benign, etc. The Table of Neoplasms should be used to identify the correct topography code. In a few cases, such as for malignant melanoma and certain neuroendocrine tumors, the morphology (histologic type) is included in the category and codes.
  • Primary malignant neoplasms overlapping site boundaries
  • A primary malignant neoplasm that overlaps two or more contiguous (next to each other) sites should be classified to the subcategory/code .8 ('overlapping lesion'), unless the combination is specifically indexed elsewhere. For multiple neoplasms of the same site that are not contiguous, such as tumors in different quadrants of the same breast, codes for each site should be assigned.
  • Malignant neoplasm of ectopic tissue
  • Malignant neoplasms of ectopic tissue are to be coded to the site mentioned, e.g., ectopic pancreatic malignant neoplasms are coded to pancreas, unspecified (C25.9).

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name C7B.8, its category, or a range that includes it.

Excludes1 2

These codes carry an Excludes1 note naming C7B.8: they are not reported together with it, unless the two conditions are unrelated.

  • C79 Secondary malignant neoplasm of other and unspecified sites
    secondary carcinoid tumors (C7B.-) names C7B.-, which includes this code
  • C79 Secondary malignant neoplasm of other and unspecified sites
    secondary neuroendocrine tumors (C7B.-) names C7B.-, which includes this code

Code Also 1

These codes say C7B.8 may also be needed to fully describe the condition. The note gives no sequencing direction.

  • E34.0 Carcinoid syndrome
    secondary neuroendocrine tumors (C7B.-) names C7B.-, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

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

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

Clinical InformationClinical

  • Metastatic Neuroendocrine Tumor

    a neuroendocrine tumor that has spread from its original site of growth to another anatomic site.

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Convert C7B.8 to ICD-9-CMHistory

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

ICD-9-CM
209.79 Sec neuroend tu oth site
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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About C7B.8Overview

What is the ICD-10 code for other secondary neuroendocrine tumors?

The ICD-10-CM code for other secondary neuroendocrine tumors is C7B.8 (sometimes written as C7B8). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is C7B.8 (Secondary neuroendocrine tumors) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other secondary neuroendocrine tumors on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does C7B.8 group to?

When other secondary neuroendocrine tumors is the principal diagnosis on an inpatient stay, it groups to MS-DRG 844, 827, 829, 843, 828, 826, 830, 845, with relative weights from 0.8443 to 4.7560 depending on complications. Higher weights mean higher Medicare reimbursement.

Is C7B.8 a CC or MCC?

CMS lists C7B.8 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 23 closely related codes in its exclusion list.

Does C7B.8 need an additional code?

When the condition applies, yes. The Use Additional Code note at C7B, which applies to C7B.8, reads: code to identify any functional activity. The additional code is reported after C7B.8.

What HCC is C7B.8?

C7B.8 (other secondary neuroendocrine tumors) maps to CMS-HCC Category 17 (Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic), commonly written as HCC 17, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 8 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 18.

Does C7B.8 risk-adjust for Medicare Advantage payment?

Yes. When documented and reported on a Medicare Advantage encounter, C7B.8 adds a risk adjustment factor of about 4.209 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 1.952 to 4.235 depending on the payment segment). HCC 17 sits at the top of its hierarchy, so no other condition category supersedes it. See the full factor table on the HCC 17 category page.