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ICD-10-CM · FY 2026 APRIL UPDATE

C4A

Merkel cell carcinoma

Diagnosis reference

Nonbillable category

This entry is a category or subcategory. Choose the appropriate billable descendant based on the clinical documentation.

Effective periodOctober 1, 2026–September 30, 2027
SourceCMS ICD-10-CM order file
ClassificationDiagnosis · clinical modification

Related entries

Up to 30 descendants in this category

CODEDESCRIPTIONTYPE
C4A.0Merkel cell carcinoma of lipBillable
C4A.1Merkel cell carcinoma of eyelid, including canthusCategory
C4A.10Merkel cell carcinoma of unspecified eyelid, including canthusBillable
C4A.11Merkel cell carcinoma of right eyelid, including canthusCategory
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 canthusCategory
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 canalCategory
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 faceCategory
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 trunkCategory
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 shoulderCategory
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 hipCategory
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

Use the complete reference

This reference does not reproduce the full tabular hierarchy, inclusion notes, Excludes1/2 notes, sequencing instructions, or seventh-character rules. Review the official tables and coding guidelines.

Open official CMS files

ICD-10-CM codes describe diagnoses. They do not have an independent Medicare PFS reimbursement amount, and billability alone does not establish coverage.