C80.1 Malignant (primary) neoplasm, unspecified

Billable ICD-10-CM code, FY2026.

Applicable to

• Cancer NOS
• Cancer unspecified site (primary)
• Carcinoma unspecified site (primary)
• Malignancy unspecified site (primary)

Excludes1 (never code together)

• secondary malignant neoplasm of unspecified site (C79.9)

Applies from C80 Malignant neoplasm without specification of site

Excludes1 (never code together)

• malignant carcinoid tumor of unspecified site (C7A.00)
• malignant neoplasm of specified multiple sites- code to each site

Risk adjustment (HCC)

• CMS-HCC V28: HCC 23 — Prostate, Breast, and Other Cancers and Tumors
• CMS-HCC V22: HCC 12 — Breast, Prostate, and Other Cancers and Tumors
• ESRD V24: HCC 12

MS-DRG index

Defines the logic of DRG(s) 826-828 in MDC 17.

Approximate ICD-9-CM (GEMs)

• 199.1 Other malignant neoplasm without specification of site (approximate)

Code annotations containing back-references to C80.1

Back-references to C80.1

• Type 1 Excludes: C76 Malignant neoplasm of other and ill-defined sites ("malignant neoplasm of unspecified site NOS (C80.1)")
• Type 1 Excludes: C79.9 Secondary malignant neoplasm of unspecified site ("malignant (primary) neoplasm of unspecified site (C80.1)")

Diagnosis Index entries for C80.1

• Cancer › unspecified site (primary)
• Carcinoma (malignant) › unspecified site (primary)
• Malignancy › unspecified site (primary)
• Sarcomatosis › unspecified site
• Tumor › malignant
• Tumor › malignant › fusiform cell (type)
• Tumor › malignant › giant cell (type)
• Tumor › malignant › mixed NEC
• Tumor › malignant › small cell (type)
• Tumor › malignant › spindle cell (type)
• Tumor › malignant › unclassified

Nearby codes

• C80 Malignant neoplasm without specification of site
• C80.0 Disseminated malignant neoplasm, unspecified
• C80.1 Malignant (primary) neoplasm, unspecified (this code)
• C80.2 Malignant neoplasm associated with transplanted organ