ICD-10-CM
ICD-10 code for Carcinoma (malignant) Merkel cell: C4A.9
The ICD-10-CM index points "Carcinoma (malignant) Merkel cell" to C4A.9, Merkel cell carcinoma, unspecified. C4A.9 is a billable code.
Source: CDC ICD-10-CM FY2027 Alphabetic Index file dated June 16, 2026. Publisher page
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Index subterms
A header groups codes and is not billed. A billable code is one you can report.
- C4A.51anal margin, Merkel cell carcinoma of anal skinBillable
- C4A.51anal skin, Merkel cell carcinoma of anal skinBillable
- C4A.30face, Merkel cell carcinoma of unspecified part of faceBillable
- C4A.0lip, Merkel cell carcinoma of lipBillable
- C4A.4neck, Merkel cell carcinoma of scalp and neckBillable
- C7B.1nodal presentation, Secondary Merkel cell carcinomaBillable
- C4A.31nose, Merkel cell carcinoma of noseBillable
- C4A.8overlapping sites, Merkel cell carcinoma of overlapping sitesBillable
- C4A.51perianal skin, Merkel cell carcinoma of anal skinBillable
- C4A.4scalp, Merkel cell carcinoma of scalp and neckBillable
- C7B.1secondary, Secondary Merkel cell carcinomaBillable
- C4A.52skin of breast, Merkel cell carcinoma of skin of breastBillable
- C4A.59trunk NEC, Merkel cell carcinoma of other part of trunkBillable
- C7B.1visceral metastatic, Secondary Merkel cell carcinomaBillable
More specific codes in C4A
A header groups codes and is not billed. A billable code is one you can report.
- C4AMerkel cell carcinomaHeader
- C4A.0Merkel cell carcinoma of lipBillable
- C4A.1Merkel cell carcinoma of eyelid, including canthusHeader
- C4A.10Merkel cell carcinoma of unspecified eyelid, including canthusBillable
- C4A.11Merkel cell carcinoma of right eyelid, including canthusHeader
- C4A.111Merkel cell carcinoma of right upper eyelid, including canthusBillable
- C4A.112Merkel cell carcinoma of right lower eyelid, including canthusBillable
- C4A.12Merkel cell carcinoma of left eyelid, including canthusHeader
- C4A.121Merkel cell carcinoma of left upper eyelid, including canthusBillable
- C4A.122Merkel cell carcinoma of left lower eyelid, including canthusBillable
- C4A.2Merkel cell carcinoma of ear and external auricular canalHeader
- C4A.20Merkel cell carcinoma of unspecified ear and external auricular canalBillable
- C4A.21Merkel cell carcinoma of right ear and external auricular canalBillable
- C4A.22Merkel cell carcinoma of left ear and external auricular canalBillable
- C4A.3Merkel cell carcinoma of other and unspecified parts of faceHeader
- C4A.30Merkel cell carcinoma of unspecified part of faceBillable
- C4A.31Merkel cell carcinoma of noseBillable
- C4A.39Merkel cell carcinoma of other parts of faceBillable
- C4A.4Merkel cell carcinoma of scalp and neckBillable
- C4A.5Merkel cell carcinoma of trunkHeader
- C4A.51Merkel cell carcinoma of anal skinBillable
- C4A.52Merkel cell carcinoma of skin of breastBillable
- C4A.59Merkel cell carcinoma of other part of trunkBillable
- C4A.6Merkel cell carcinoma of upper limb, including shoulderHeader
- C4A.60Merkel cell carcinoma of unspecified upper limb, including shoulderBillable
- C4A.61Merkel cell carcinoma of right upper limb, including shoulderBillable
- C4A.62Merkel cell carcinoma of left upper limb, including shoulderBillable
- C4A.7Merkel cell carcinoma of lower limb, including hipHeader
- C4A.70Merkel cell carcinoma of unspecified lower limb, including hipBillable
- C4A.71Merkel cell carcinoma of right lower limb, including hipBillable
- C4A.72Merkel cell carcinoma of left lower limb, including hipBillable
- C4A.8Merkel cell carcinoma of overlapping sitesBillable
- C4A.9Merkel cell carcinoma, unspecifiedBillable
Related conditions
Related pages
- C4A.9 code detailsNotes, nearby codes, CMS-HCC group
- Category C4AEvery code under it
- Chapter 2Neoplasms
- ICD-10 codes by conditionA to Z
- Check a list of ICD-10 codes
- Denial code CO-11Diagnosis does not support the procedure
- Denial code CO-146Diagnosis invalid for the date of service
- HCPCS Level II code lookup
Questions
What is the ICD-10 code for Carcinoma (malignant) Merkel cell?
The ICD-10-CM index points "Carcinoma (malignant) Merkel cell" to C4A.9, Merkel cell carcinoma, unspecified. C4A.9 is a billable code.
Is C4A.9 billable?
Yes. C4A.9 is a billable code in the FY2027 ICD-10-CM file. Use a more specific code when the record documents one.
What chapter is C4A.9 in?
Chapter 2. Neoplasms.
When do ICD-10-CM codes change?
Every October 1, with the new fiscal year file. Some years add April 1 updates. This page uses the FY2027 file, effective October 1, 2026.