2026 ICD-10-CM Diagnosis Code C7B.1Secondary Merkel cell carcinoma

ICD-10-CM Codes›C00–D49›C7B›C7B

ICD-10-CM C7B.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

C7B.1 is a billable ICD-10-CM diagnosis code for secondary Merkel cell carcinoma. 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
C7B.1
Billable Status
Yes — Valid for Submission
Code Describes
Secondary Merkel cell carcinoma
Short Description
Secondary Merkel cell carcinoma
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.1Secondary Merkel cell carcinoma

Tabular List NotesGuidance

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

Inclusion Terms

  • Merkel cell carcinoma nodal presentation
  • Merkel cell carcinoma visceral metastatic presentation

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)
      • Merkel cell
        • nodal presentation
    • Carcinoma(malignant)
      • Merkel cell
        • secondary
    • Carcinoma(malignant)
      • Merkel cell
        • visceral metastatic
    • Carcinoma(malignant)
      • secondary
        • Merkel cell

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

Skin Cancer

Skin cancer is the most common form of cancer in the United States. The two most common types are basal cell cancer and squamous cell cancer. They usually form on the head, face, neck, hands, and arms. Another type of skin cancer, melanoma, is more dangerous but less common.

Read the full article at MedlinePlus

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

Convert C7B.1 to ICD-9-CMHistory

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

ICD-9-CM
209.75 Secondary Merkel cell ca
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 C7B.1Overview

Is C7B.1 (Secondary neuroendocrine tumors) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report secondary Merkel cell carcinoma on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does C7B.1 group to?

When secondary Merkel cell carcinoma 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 C7B.1?

Under the General Equivalence Mappings, secondary Merkel cell carcinoma converts to ICD-9-CM 209.75 (secondary Merkel cell ca). 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.