Skip to content
Dx

ICD-10-CM 2027

ICD-10 code for malignant tumor

C80.1

Malignant (primary) neoplasm, unspecified

✓ Billable / specific

From the official ICD-10-CM alphabetic index entry “Tumor › malignant”. Page updated September 29, 2026.

About coding malignant tumor

The ICD-10-CM code for malignant tumor is C80.1 (Malignant (primary) neoplasm, unspecified). The official index lists 6 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on C80.1.

Within C80, choose C80.1 (Malignant (primary) neoplasm, unspecified) only when documentation doesn't support a more specific option: disseminated malignant neoplasm, unspecified (C80.0) and malignant neoplasm associated with transplanted organ (C80.2).

Don't report C80.1 together with the conditions in its Excludes1 note: secondary malignant neoplasm of unspecified site (C79.9).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

More specific malignant tumor codes (official index)

  • fusiform cell (type) C80.1 — Malignant (primary) neoplasm, unspecified
  • giant cell (type) C80.1 — Malignant (primary) neoplasm, unspecified
  • localized, plasma cell
  • mixed NEC C80.1 — Malignant (primary) neoplasm, unspecified
  • small cell (type) C80.1 — Malignant (primary) neoplasm, unspecified
  • spindle cell (type) C80.1 — Malignant (primary) neoplasm, unspecified
  • unclassified C80.1 — Malignant (primary) neoplasm, unspecified

Don't confuse with (Excludes1 for C80.1)

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

Common questions about malignant tumor ICD-10 codes

What is the ICD-10 code for malignant tumor?

C80.1 — Malignant (primary) neoplasm, unspecified. More specific codes apply when the documentation supports them: C80.1, C80.1, C80.1, C80.1 and others below.

What is the ICD-10 code for fusiform cell malignant tumor?

C80.1 — Malignant (primary) neoplasm, unspecified.

What is the ICD-10 code for giant cell malignant tumor?

C80.1 — Malignant (primary) neoplasm, unspecified.

What is the ICD-10 code for mixed nec malignant tumor?

C80.1 — Malignant (primary) neoplasm, unspecified.

What is the ICD-10 code for small cell malignant tumor?

C80.1 — Malignant (primary) neoplasm, unspecified.

What is the ICD-10 code for spindle cell malignant tumor?

C80.1 — Malignant (primary) neoplasm, unspecified.

What is the ICD-10 code for unclassified malignant tumor?

C80.1 — Malignant (primary) neoplasm, unspecified.

Is C80.1 billable?

Yes. C80.1 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can C80.1 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict C80.1 as a principal diagnosis.

Is C80.1 a CC or MCC?

No. C80.1 is neither a CC nor an MCC under MS-DRG v44.0.