C80.0 Disseminated malignant neoplasm, unspecified

The ICD-10-CM code for Disseminated malignant neoplasm, unspecified is C80.0 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Chapter

2: Neoplasms (C00-D49)

Section

C76-C80: Malignant neoplasms of ill-defined, other secondary and unspecified sites (C76-C80)

Category C80

4 codes (3 billable)

FY2026 Status

Stable since FY2024

Also Known As

ICD-10-CM Alphabetic Index entries that lead to C80.0:

• Carcinomatosis
• Carcinomatosis › unspecified site (primary) (secondary)
• Carcinoma (malignant) › generalized, with unspecified primary site

Inclusion Terms

• Carcinomatosis NOS
• Generalized cancer, unspecified site (primary) (secondary)
• Generalized malignancy, unspecified site (primary) (secondary)

U.S. Hospital Utilization

• An estimated 4,470 U.S. inpatient stays in 2023 included C80.0 among the documented diagnoses.
• 440 stays listed it as the principal diagnosis.

Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.

Official Coding Guidelines

C80.0 disseminated malignant neoplasm—limited use

j. Disseminated malignant neoplasm, unspecified Code C80.0, Disseminated malignant neoplasm, unspecified, is for use only in those cases where the patient has advanced metastatic disease and no known primary or secondary sites are specified. It should not be used in place of assigning codes for the primary site and all known secondary sites.

Tx of primary site (TOC entry)

a. Admission/Encounter for treatment of primary site ............................................................. 33

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool
• AHRQ — HCUP National Inpatient Sample, Frequencies by Diagnosis Code (2016–2023)