2026 ICD-10-CM Diagnosis Code C10.4Malignant neoplasm of branchial cleft

ICD-10-CM Codes›C00–D49›C00-C14›C10

ICD-10-CM C10.4
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

C10.4 is a billable ICD-10-CM diagnosis code for malignant neoplasm of branchial cleft. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 146 through 148. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Head and neck cancers - throat.

Code Identity

ICD-10-CM Code
C10.4
Billable Status
Yes — Valid for Submission
Code Describes
Malignant neoplasm of branchial cleft
Short Description
Malignant neoplasm of branchial cleft
Same as the full description in the CMS dataset.
Parent Code
C10
Malignant neoplasm of oropharynx

Code Classification

ChapterC00–D49Neoplasms
SectionC00-C14Malignant neoplasms of lip, oral cavity and pharynx
CategoryC10Malignant neoplasm of oropharynx
This CodeC10.4Malignant neoplasm of branchial cleft

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Malignant neoplasm of branchial cleft
  • Primary malignant neoplasm of branchial cleft
  • Primary squamous cell carcinoma of branchial cleft

Tabular List NotesGuidance

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

Inclusion Terms

  • Malignant neoplasm of branchial cyst site of neoplasm

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)
      • branchial or branchiogenic

Clinical ClassificationClinical

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

CCSR NEO003
Head and neck cancers - throat
Default principal diagnosis: inpatient Yes · outpatient Yes

Table of NeoplasmsClinical

Anatomical sites in the Table of Neoplasms that reference this code family.

SiteMalig.
Primary		Malig.
Secondary		Ca
in situ		BenignUncertainUnspec.
branchial (cleft) (cyst) (vestiges)C10.4C79.89D00.08D10.5D37.05D49.0
oropharynx › branchial cleft (vestige)C10.4C79.89D00.08D10.5D37.05D49.0

Patient EducationClinical

Throat Cancer

Throat cancer is a type of head and neck cancer. Throat cancer has different names, depending on which part of the throat is affected. The different parts of your throat are called the oropharynx, the hypopharynx, the nasopharynx, and the larynx, or voice box.

Read the full article at MedlinePlus

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

Convert C10.4 to ICD-9-CMHistory

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

ICD-9-CM
146.8 Mal neo oropharynx NEC
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 C10.4Overview

Is C10.4 (Malignant neoplasm of oropharynx) a billable code?

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

What MS-DRG does C10.4 group to?

When malignant neoplasm of branchial cleft is the principal diagnosis on an inpatient stay, it groups to MS-DRG 146, 147, 148, with relative weights from 0.7971 to 2.1174 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of C10.4?

Under the General Equivalence Mappings, malignant neoplasm of branchial cleft converts to ICD-9-CM 146.8 (mal neo oropharynx NEC). 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.