Loading...

    Explore
    • Policy Monitoring
    • Live Policy Feed
    • Billing Codes
    • NPI Medicare & Medicaid
    • Healthcare Providers
    • Health Insurance Payers
    • States
    • Service Lines
    • Taxonomy Codes
    Lookup tools
    • Billing Code Lookup
    • CPT Modifier Lookup
    • Provider Taxonomy Code Lookup
    • Healthcare Provider & Facility Lookup
    • Health Insurance Payer Lookup
    • Payer Contact Directory

    Policy & Benchmark Tools

    • Prior Authorization Lookup
    • Coverage Criteria Lookup
    • Timely Filing Lookup
    • Billing Code Reimbursement Rates
    • Payer Comparison Dashboard
    • Facility Comparison Dashboard
    • All tools

    Company

    • About OpenPayer
    • Data Sources
    • Trek Health
    OpenPayerby Trek Health
    LinkedInYouTube

    © 2026 Trek Health. All rights reserved.

    OpenPayer is built and maintained by Trek Health.

    v1.0.28
    OpenPayerBilling CodesMalignant neoplasms of ill-defined, other secondary and unspecified sitesICD-10-CM c80-malignant-neoplasm-unspecified
    Ask Trek AI about this page

    ICD-10-CM Code For Malignant Neoplasm Without Specification Of Site: Group Overview

    The International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) code group C80 includes malignant neoplasms that are unspecified by primary site and covers cancers documented as metastatic without a known origin or labeled as malignant neoplasm without specification of site. These ICD-10-CM diagnosis codes are used to document clinical scenarios where the primary tumor cannot be identified, where only metastatic disease is recorded, or when diagnostic information is incomplete, capturing disease extent and diagnostic uncertainty. Accurate coding within the ICD-10-CM C80 group supports proper claim adjudication, complete clinical documentation, and appropriate reimbursement.

    Customize your policy alerts

    Sign up for ICD-10-CM Code For Malignant Neoplasm Without Specification Of Site: Group Overview policy alerts

    Get alerted when relevant policies change without checking for updates manually.

    Monitor payer policy activity

    Receive email alerts as soon as relevant payer policies are published or updated.

    ICD-10-CM C80: Malignant Neoplasm Without Specification Of Site Overview

    The ICD-10-CM C80 group represents malignant neoplasms for which the primary site is not specified or cannot be determined. These diagnoses target systemic cancer presentations or cases where the originating organ is unknown, often encountered in metastatic disease workups. Accurate coding matters for clinical records and can affect reimbursement and care coordination by reflecting diagnostic uncertainty.

    Table of contents

    Progress1 / 6

    Explore openpayer tools

    • Billing CodesCPT, HCPCS, DRG & more
    • Reimbursement RatesCommercial vs. Medicare rate reports
    • ProvidersHospitals & facilities
    • PayersPlans & market footprint
    • Taxonomy CodesNUCC specialty codes
    • ModifiersCPT modifiers & usage
    • Prior AuthorizationPA policies by payer & drug
    • Timely FilingFiling deadlines by payer
    • Coverage CriteriaMedical necessity by payer
    • Payer ContactsClaims, PA & appeals contacts
    View all tools

    When to Use

    Use a code from this group when clinical documentation indicates a malignant neoplasm but does not identify the primary organ or site, or when only metastatic disease is documented without a known origin. Do not use these codes if a more specific primary site code is available in the medical record.

    ICD-10-CM Codes

    3 rows

    ICD-10-CM CodeDescription
    C80.0Disseminated malignant neoplasm, unspecified
    C80.1Malignant (primary) neoplasm, unspecified
    C80.2Malignant neoplasm associated with transplanted organ

    DRG Codes

    8 rows

    DRG CodeDescription
    826Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Major O.R. Procedures with MCC
    827Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Major O.R. Procedures with CC
    828Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Major O.R. Procedures without CC/MCC
    829Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Other Procedures with CC/MCC
    830Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Other Procedures without CC/MCC
    843Other Myeloproliferative Disorders or Poorly Differentiated Neoplastic Diagnoses with MCC
    844Other Myeloproliferative Disorders or Poorly Differentiated Neoplastic Diagnoses with CC
    845Other Myeloproliferative Disorders or Poorly Differentiated Neoplastic Diagnoses without CC/MCC

    Typical Clinical Scenarios

    • An elderly patient with rapidly progressive weight loss, fatigue, and widespread metastatic symptoms presents to the emergency department with severe dyspnea and altered mental status. Imaging shows multiple metastatic lesions throughout the chest and liver, but the primary tumor cannot be identified after initial workup and stabilization is the immediate priority; a diagnosis from this group is assigned to document malignant neoplasm without specification of site when the primary site remains unknown. Typical codes: C80.1, C80.2
    • A patient with a history of cancer treated years ago develops new, non-specific systemic symptoms and multiple metastatic deposits on PET/CT, but prior records are unavailable and definitive histopathology cannot localize the origin; outpatient oncology assigns a code to indicate malignancy where the specific primary site is unspecified while further diagnostic evaluation is planned. Typical codes: C80.2, C80.1
    • A hospitalized patient with advanced cachexia and complications of disseminated malignancy is receiving palliative care when the team documents a malignant neoplasm without specification of site because biopsies are non-diagnostic and the clinical course is dominated by terminal cancer of unknown primary; coding reflects the presence of an unspecified malignant neoplasm as the principal condition affecting care. Typical codes: C80.0, C80.2

    Related Codes

    C76-MALIGNANT-NEOPLASM-OTHER-ILL-DEFINED-SITES

    ICD-10-CM Code For Malignant Neoplasm Of Other And Ill-Defined Sites: Group Overview

    C77-SECONDARY-AND-UNSPECIFIED-LYMPH-NODE-NEOPLASMS

    ICD-10-CM Code For Secondary And Unspecified Malignant Neoplasm Of Lymph Nodes: Group Overview

    C78-SECONDARY-MALIGNANT-NEOPLASM-RESPIRATORY-DIGESTIVE

    ICD-10-CM Code For Secondary Malignant Neoplasm Of Respiratory And Digestive Organs: Group Overview

    C79-SECONDARY-MALIGNANT-NEOPLASM

    ICD-10-CM Code For Secondary Malignant Neoplasm Of Other And Unspecified Sites: Group Overview

    Frequently Asked Questions

    References

    1. 1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
    2. 2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
    3. 3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.
    Published by

    Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

    Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.