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ICD-10-CM 2027 diagnosis code

C4A.3Merkel cell carcinoma of other and unspecified parts of face

Not billable — use a more specific code

C4A.3 is a header code, so it can't be reported by itself. Choose one of the 3 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About C4A.3

C4A.3 is the ICD-10-CM diagnosis code for Merkel cell carcinoma of other and unspecified parts of face. It belongs to category C4A (Merkel cell carcinoma), block C43-C44 (melanoma and other malignant neoplasms of skin) and chapter 2 (neoplasms). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.

Within C4A, choose C4A.3 (of other and unspecified parts of face) only when documentation doesn't support a more specific option: of lip (C4A.0), of eyelid, including canthus (C4A.1), of ear and external auricular canal (C4A.2), of scalp and neck (C4A.4), of trunk (C4A.5), of upper limb, including shoulder (C4A.6), of lower limb, including hip (C4A.7), of overlapping sites (C4A.8) and 1 more.

To report this condition, pick the subcode that matches the documentation: C4A.30 (face), C4A.31 (nose) and C4A.39 (face).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under C4A.3

Notes that apply from higher levels

Instructions written at a parent level also apply to C4A.3.

Broader instructions also apply from Chapter 2: Neoplasms.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about C4A.3

Is C4A.3 billable?

No. C4A.3 is a header code. Report one of its more specific subcodes instead.