2026 ICD-10-CM Diagnosis Code C34.90Malignant neoplasm of unspecified part of unspecified bronchus or lung

ICD-10-CM Codes›C00–D49›C30-C39›C34

ICD-10-CM C34.90
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

C34.90 is a billable ICD-10-CM diagnosis code for malignant neoplasm of unspecified part of unspecified bronchus or lung. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 180 through 182. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Respiratory cancers.

Code Identity

ICD-10-CM Code
C34.90
Billable Status
Yes — Valid for Submission
Code Describes
Malignant neoplasm of unspecified part of unspecified bronchus or lung
Short Description
Malignant neoplasm of unsp part of unsp bronchus or lung
Parent Code
C34.9
Malignant neoplasm of unspecified part of bronchus or lung

Code Classification

ChapterC00–D49Neoplasms
SectionC30-C39Malignant neoplasms of respiratory and intrathoracic organs
CategoryC34Malignant neoplasm of bronchus and lung
This CodeC34.90Malignant neoplasm of unspecified part of unspecified bronchus or lung

Quality Payment Program MeasuresBilling

Medicare quality measures that can apply when C34.90 is part of the patient record.

Lung Cancer Reporting (Biopsy/Cytology Specimens)

High Priority: YES

Measure Type: Process

Submission Methods: Claims, Registry

Description: Pathology reports based on lung biopsy and/or cytology specimens with a diagnosis of primary non-small cell lung cancer classified into specific histologic type following the International Association for the Study of Lung Cancer (IASLC) guidance or classified as non-small cell lung cancer not otherwise specified (NSCLC-NOS) with an explanation included in the pathology report.

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Lung Cancer Reporting (Resection Specimens)

High Priority: YES

Measure Type: Process

Submission Methods: Claims, Registry

Description: Pathology reports based on lung resection specimens with a diagnosis of primary lung carcinoma that include the pT category, pN category and for non-small cell lung cancer (NSCLC), histologic type.

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Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acinar cell carcinoma of lung
  • Acinar cell cystadenocarcinoma of lung
  • Adenocarcinoma of lung
  • Adenocarcinoma of lung, stage I
  • Adenocarcinoma of lung, stage II
  • Adenocarcinoma of lung, stage III
  • Adenocarcinoma of lung, stage IV
  • Adenoid cystic carcinoma of lung
  • Adenosquamous carcinoma of lung
  • Anaplastic lymphoma kinase fusion oncogene negative non-small cell lung cancer
  • Anaplastic lymphoma kinase fusion oncogene positive non-small cell lung cancer
  • Basaloid squamous cell carcinoma of lung
  • Carcinoma of lung
  • Carcinosarcoma of lung
  • Clear cell adenocarcinoma of lung
  • Clear cell squamous cell carcinoma of lung
  • Combined small cell carcinoma of lung
  • Epidermal growth factor receptor negative non-small cell lung cancer
  • Epidermal growth factor receptor positive non-small cell lung cancer
  • Epithelioid hemangioendothelioma
  • Epithelioid hemangioendothelioma of lung
  • Extensive stage primary small cell carcinoma of lung
  • Fetal adenocarcinoma of lung
  • Giant cell carcinoma of lung
  • Large cell carcinoma of lung
  • Large cell carcinoma of lung, TNM stage 1
  • Large cell carcinoma of lung, TNM stage 2
  • Large cell carcinoma of lung, TNM stage 3
  • Large cell carcinoma of lung, TNM stage 4
  • Local recurrence of malignant neoplasm of lung
  • Malignant epithelial neoplasm of bronchus
  • Malignant neoplasm of bronchus
  • Malignant neoplasm of lung
  • Malignant neoplasm of lung parenchyma
  • Mixed mucinous and non-mucinous bronchiolo-alveolar carcinoma of lung
  • Mixed subtype adenocarcinoma of lung
  • Mucinous adenocarcinoma of lung
  • Mucinous bronchiolo-alveolar carcinoma of lung
  • Mucinous cystadenocarcinoma of lung
  • Mucoepidermoid carcinoma of lung
  • Myoepithelial carcinoma
  • Myoepithelial carcinoma of lung
  • Neoplasm of blood vessel of thorax
  • Non-mucinous bronchiolo-alveolar carcinoma of lung
  • Non-small cell adenocarcinoma of lung
  • Non-small cell carcinoma of lung, TNM stage 1
  • Non-small cell carcinoma of lung, TNM stage 2
  • Non-small cell carcinoma of lung, TNM stage 3
  • Non-small cell carcinoma of lung, TNM stage 4
  • Non-small cell lung cancer
  • Non-small cell lung cancer with mutation in epidermal growth factor receptor
  • Non-small cell lung cancer without mutation in epidermal growth factor receptor
  • Non-small cell lung carcinoma with NRG1 fusion
  • Nonsquamous nonsmall cell neoplasm of lung
  • Papillary adenocarcinoma of lung
  • Papillary squamous cell carcinoma of lung
  • Pleomorphic carcinoma of lung
  • Pleuropulmonary blastoma
  • Pleuropulmonary blastoma type I
  • Pleuropulmonary blastoma type II
  • Pleuropulmonary blastoma type III
  • Primary acinar cell carcinoma of lung
  • Primary acinar cell cystadenocarcinoma of lung
  • Primary adenocarcinoma of lung
  • Primary adenoid cystic carcinoma of lung
  • Primary adenosquamous carcinoma of lung
  • Primary adenosquamous cell carcinoma
  • Primary anaplastic lymphoma kinase fusion oncogene negative non-small cell lung cancer
  • Primary anaplastic lymphoma kinase fusion oncogene positive non-small cell lung cancer
  • Primary basaloid squamous cell carcinoma of lung
  • Primary carcinosarcoma of lung
  • Primary clear cell adenocarcinoma of lung
  • Primary clear cell squamous cell carcinoma of lung
  • Primary epidermal growth factor receptor negative non-small cell lung cancer
  • Primary epidermal growth factor receptor positive non-small cell lung cancer
  • Primary epithelioid hemangioendothelioma
  • Primary epithelioid hemangioendothelioma of lung
  • Primary fetal adenocarcinoma of lung
  • Primary giant cell carcinoma of lung
  • Primary large cell carcinoma of lung
  • Primary malignant neoplasm of blood vessel of thorax
  • Primary malignant neoplasm of blood vessel of trunk
  • Primary malignant neoplasm of bronchus
  • Primary malignant neoplasm of lung
  • Primary mixed mucinous and non-mucinous bronchiolo-alveolar carcinoma of lung
  • Primary mixed subtype adenocarcinoma of lung
  • Primary mucinous adenocarcinoma of lung
  • Primary mucinous bronchiolo-alveolar carcinoma of lung
  • Primary mucinous cystadenocarcinoma of lung
  • Primary mucoepidermoid carcinoma of lung
  • Primary myoepithelial carcinoma of lung
  • Primary non-mucinous bronchiolo-alveolar carcinoma of lung
  • Primary non-small cell lung cancer
  • Primary non-small cell lung cancer with mutation in epidermal growth factor receptor
  • Primary non-small cell lung cancer without mutation in epidermal growth factor receptor
  • Primary non-small cell lung carcinoma with NRG1 fusion
  • Primary nonsquamous nonsmall cell neoplasm of lung
  • Primary papillary adenocarcinoma of lung
  • Primary papillary squamous cell carcinoma of lung
  • Primary pleomorphic carcinoma of lung
  • Primary pleuropulmonary blastoma
  • Primary pseudosarcomatous carcinoma of lung
  • Primary pulmonary blastoma
  • Primary reactive oxygen species 1 negative non-small cell lung cancer
  • Primary reactive oxygen species 1 positive non-small cell lung cancer
  • Primary salivary gland type carcinoma of lung
  • Primary signet ring cell carcinoma of lung
  • Primary small cell carcinoma of lung
  • Primary small cell malignant neoplasm of lung, TNM stage 1
  • Primary small cell malignant neoplasm of lung, TNM stage 2
  • Primary small cell malignant neoplasm of lung, TNM stage 3
  • Primary small cell malignant neoplasm of lung, TNM stage 4
  • Primary small cell non-keratinizing squamous cell carcinoma of lung
  • Primary solid carcinoma of lung
  • Primary spindle cell carcinoma of lung
  • Primary squamous cell carcinoma of bronchus
  • Primary squamous cell carcinoma of lung
  • Primary squamous non-small cell lung cancer
  • Primary undifferentiated carcinoma of lung
  • Pseudosarcomatous carcinoma of lung
  • Pulmonary blastoma
  • Reactive oxygen species 1 negative non-small cell lung cancer
  • Reactive oxygen species 1 positive non-small cell lung cancer
  • Salivary gland type carcinoma of lung
  • Signet ring cell carcinoma of lung
  • Small cell carcinoma of lung
  • Small cell non-keratinizing squamous cell carcinoma of lung
  • Solid carcinoma of lung
  • Spindle cell carcinoma of lung
  • Squamous cell carcinoma of bronchus
  • Squamous cell carcinoma of lung
  • Squamous cell carcinoma of lung, TNM stage 1
  • Squamous cell carcinoma of lung, TNM stage 2
  • Squamous cell carcinoma of lung, TNM stage 3
  • Squamous cell carcinoma of lung, TNM stage 4
  • Squamous non-small cell lung cancer
  • Undifferentiated carcinoma of lung

Tabular List NotesGuidance

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

Inclusion Terms

  • Lung cancer NOS

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

  • - Cancer - See Also: Neoplasm, by site, malignant;

    • - lung - See Also: Neoplasm, lung, malignant; - C34.90

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Cancer
      • lung
    • Carcinoma(malignant)
      • large cell
        • small cell
          • unspecified site
    • Carcinoma(malignant)
      • oat cell
        • unspecified site
    • Carcinoma(malignant)
      • small cell
        • fusiform cell
          • unspecified site
    • Carcinoma(malignant)
      • small cell
        • intermediate cell
          • unspecified site
    • Carcinoma(malignant)
      • small cell
        • large cell
          • unspecified site

Clinical ClassificationClinical

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

CCSR NEO022
Respiratory cancers
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Pulmonary Blastoma

    a malignant neoplasm of the lung composed chiefly or entirely of immature undifferentiated cells (i.e., blast forms) with little or virtually no stroma. (from stedman, 25th ed)

  • Adenocarcinoma of Lung

    a carcinoma originating in the lung and the most common lung cancer type in never-smokers. malignant cells exhibit distinct features such as glandular epithelial, or tubular morphology. mutations in kras, egfr, braf, and erbb2 genes are associated with this cancer.

Table of NeoplasmsClinical

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

SiteMalig.
Primary		Malig.
Secondary		Ca
in situ		BenignUncertainUnspec.
bronchiogenic, bronchogenic (lung)C34.9C78.0D02.2D14.3D38.1D49.1
bronchioleC34.9C78.0D02.2D14.3D38.1D49.1
bronchusC34.9C78.0D02.2D14.3D38.1D49.1
lungC34.9C78.0D02.2D14.3D38.1D49.1
lung › lobe NECC34.9C78.0D02.2D14.3D38.1D49.1
pulmonary [See Also: Neoplasm, lung]C34.9C78.0D02.2D14.3D38.1D49.1
subpleuralC34.9C78.0D02.2D14.3D38.1D49.1

Patient EducationClinical

Lung Cancer

Lung cancer is cancer that forms in tissues of the lung, usually in the cells that line the air passages. It is the leading cause of cancer death in both men and women.

The full article covers:

  • What is lung cancer?
  • Who is more likely to develop lung cancer?
  • What are the symptoms of lung cancer?
  • How is lung cancer diagnosed?
  • What are the treatments for lung cancer?
  • Can lung cancer be prevented?

Read the full article at MedlinePlus

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

Convert C34.90 to ICD-9-CMHistory

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

ICD-9-CM
162.9 Mal neo bronch/lung 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 C34.90Overview

Is C34.90 (Malignant neoplasm of unspecified part of bronchus or lung) a billable code?

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

What MS-DRG does C34.90 group to?

When malignant neoplasm of unspecified part of unspecified bronchus or lung is the principal diagnosis on an inpatient stay, it groups to MS-DRG 180, 181, 182, with relative weights from 0.7440 to 1.7660 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of C34.90?

Under the General Equivalence Mappings, malignant neoplasm of unspecified part of unspecified bronchus or lung converts to ICD-9-CM 162.9 (mal neo bronch/lung 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.