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  5. C4A
  6. 2024 ICD-10-CM Code C4A.1
Version 2024
Non-Billable Code

2024 ICD-10-CM Diagnosis Code C4A.1

Merkel cell carcinoma of eyelid, including canthus

ICD-10-CM Code:
C4A.1
ICD-10 Code for:
Merkel cell carcinoma of eyelid, including canthus
Is Billable?
Not Valid for Submission
Code Navigator:

Code Classification

  • Neoplasms
    (C00–D49)
    • Melanoma and other malignant neoplasms of skin
      (C43-C44)
      • Merkel cell carcinoma
        (C4A)

C4A.1 is a non-specific and non-billable diagnosis code code, consider using a code with a higher level of specificity for a diagnosis of merkel cell carcinoma of eyelid, including canthus. The code is not specific and is NOT valid for the year 2024 for the submission of HIPAA-covered transactions. Category or Header define the heading of a category of codes that may be further subdivided by the use of 4th, 5th, 6th or 7th characters.

Specific Coding Applicable to Merkel cell carcinoma of eyelid, including canthus

Non-specific codes like C4A.1 require more digits to indicate the appropriate level of specificity. Consider using any of the following ICD-10-CM codes with a higher level of specificity when coding for merkel cell carcinoma of eyelid, including canthus:

  • Use C4A.10 for Merkel cell carcinoma of unspecified eyelid, including canthus - BILLABLE CODE

  • C4A.11 for Merkel cell carcinoma of right eyelid, including canthus - NON-BILLABLE CODE

  • Use C4A.111 for Merkel cell carcinoma of right upper eyelid, including canthus - BILLABLE CODE

  • Use C4A.112 for Merkel cell carcinoma of right lower eyelid, including canthus - BILLABLE CODE

  • C4A.12 for Merkel cell carcinoma of left eyelid, including canthus - NON-BILLABLE CODE

  • Use C4A.121 for Merkel cell carcinoma of left upper eyelid, including canthus - BILLABLE CODE

  • Use C4A.122 for Merkel cell carcinoma of left lower eyelid, including canthus - BILLABLE CODE

Index to Diseases and Injuries References

The following annotation back-references for this diagnosis code are found in the injuries and diseases index. The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10-CM code(s).

Patient Education


Skin Cancer

Skin cancer is the most common form of cancer in the United States. The two most common types are basal cell cancer and squamous cell cancer. They usually form on the head, face, neck, hands, and arms. Another type of skin cancer, melanoma, is more dangerous but less common.

Anyone can get skin cancer, but it is more common in people who :

  • Spend a lot of time in the sun or have been sunburned
  • Have light-colored skin, hair and eyes
  • Have a family member with skin cancer
  • Are over age 50

You should have your doctor check any suspicious skin markings and any changes in the way your skin looks. Treatment is more likely to work well when cancer is found early. If not treated, some types of skin cancer cells can spread to other tissues and organs. Treatments include surgery, radiation therapy, chemotherapy, photodynamic therapy (PDT), and biologic therapy. PDT uses a drug and a type of laser light to kill cancer cells. Biologic therapy boosts your body's own ability to fight cancer.

NIH: National Cancer Institute


[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.