C4A.9

Billable code

Merkel cell carcinoma, unspecified

The ICD-10 code for merkel cell carcinoma, unspecified is C4A.9.

Clinical notes

Also known as

Alternate wording, synonyms, or specific conditions that fall under this code, listed to help confirm you've picked the right one.

Merkel cell carcinoma of unspecified site
Merkel cell carcinoma NOS

Documentation support

General coding-documentation guidance — not a substitute for payer-specific requirements or professional coding judgment.

•This code describes an unspecified presentation. If the medical record documents a more specific detail (e.g. laterality, type, or affected site), a more specific sibling code should be used instead — see Related codes below.
•As a general rule, code to the highest level of specificity supported by the documentation in the medical record.

Related codes in this category

ICD-9-CM equivalent

Informational only — GEM mappings are approximate, not guaranteed one-to-one equivalents. Verify before use in billing.

20936Approximate match

View full ICD-10 → ICD-9 crosswalk →

Associated MS-DRGs

C4A.9 can serve as the principal diagnosis for these Medicare Severity Diagnosis-Related Groups.

Informational only — actual DRG assignment also depends on procedures, complications/comorbidities (CC/MCC), discharge status, and payer-specific rules not reflected here.