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.
Official description
C4AMerkel cell carcinoma
ICD-10-CM diagnosis code · United States clinical modification
Where C4A sits
- 1
Chapter 2
Neoplasms (C00-D49)
- 2
Section
Malignant neoplasms (C00-C96)
- 3
Category C4A
Merkel cell carcinoma
- 4
Code C4A
Merkel cell carcinoma
Codes under C4A
C4A is a non-billable category. Choose the child code that best matches the documented diagnosis.
C4A.0Merkel cell carcinoma of lipC4A.1Merkel cell carcinoma of eyelid, including canthusC4A.2Merkel cell carcinoma of ear and external auricular canalC4A.3Merkel cell carcinoma of other and unspecified parts of faceC4A.4Merkel cell carcinoma of scalp and neckC4A.5Merkel cell carcinoma of trunkC4A.6Merkel cell carcinoma of upper limb, including shoulderC4A.7Merkel cell carcinoma of lower limb, including hipC4A.8Merkel cell carcinoma of overlapping sitesC4A.9Merkel cell carcinoma, unspecifiedNotes 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.
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.
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.