U.S. ICD-10-CM · FY 2027

C4A ICD-10-CM Code: Merkel cell carcinoma

A clear reference for the official code description, hierarchy, and related coding information from the FY 2027 U.S. release.

Code definition

Official description

C4A

Merkel cell carcinoma

ICD-10-CM diagnosis code · United States clinical modification

Classification

Where C4A sits

  1. 1

    Chapter 2

    Neoplasms (C00-D49)

  2. 2

    Section

    Malignant neoplasms (C00-C96)

  3. 3

    Category C4A

    Merkel cell carcinoma

  4. 4

    Code C4A

    Merkel cell carcinoma

More specific choices

Codes under C4A

C4A is a non-billable category. Choose the child code that best matches the documented diagnosis.

C4A.0

Merkel cell carcinoma of lip

C4A.1

Merkel cell carcinoma of eyelid, including canthus

C4A.2

Merkel cell carcinoma of ear and external auricular canal

C4A.3

Merkel cell carcinoma of other and unspecified parts of face

C4A.4

Merkel cell carcinoma of scalp and neck

C4A.5

Merkel cell carcinoma of trunk

C4A.6

Merkel cell carcinoma of upper limb, including shoulder

C4A.7

Merkel cell carcinoma of lower limb, including hip

C4A.8

Merkel cell carcinoma of overlapping sites

C4A.9

Merkel cell carcinoma, unspecified

Documentation details

Notes for this code

Inclusion terms

No inclusion terms are listed for C4A.

Code first

No “code first” instruction is listed for C4A.

Use additional code

No “use additional code” instruction is listed for C4A.

Excludes1

Conditions that should not be reported together with this code.

No Excludes1 note is listed for C4A.

Excludes2

Conditions not included here that may be reported separately when present.

No Excludes2 note is listed for C4A.

Transparency

Source and release

Data release

U.S. ICD-10-CM · FY 2027

Effective date

Oct 1, 2026

Publisher

Vero Scribe Inc.

This reference is generated from Vero’s ICD-10-CM description, hierarchy, and code-note dataset. The visible content and structured data share that source.

Review the CDC/NCHS ICD-10-CM source

Code-specific guidance

Frequently asked questions

What does ICD-10-CM code C4A mean?

C4A is the FY 2027 U.S. ICD-10-CM code for “Merkel cell carcinoma.”

Is C4A a billable or specific ICD-10-CM code?

No. C4A has more specific child codes in the FY 2027 reference data. Select the code that matches the documentation and confirm the active code set and payer requirements.

Where is C4A located in ICD-10-CM?

C4A is listed in Chapter 2, Neoplasms (C00-D49), within Malignant neoplasms (C00-C96) (C00–C96), under category C4A, Merkel cell carcinoma.

What coding notes are listed for C4A?

No inclusion terms are listed for C4A in this reference record. No code-first instruction is listed. No Excludes1 note is listed. No Excludes2 note is listed.

Ready to transform your clinical documentation?

Join Vero and see how effortless documentation can be.

Try for free

  • No credit card required

  • Cancel anytime