2022 ICD-10-CM Code C4A

Merkel cell carcinoma

Version 2021

Not Valid for Submission

ICD-10:C4A
Short Description:Merkel cell carcinoma
Long Description:Merkel cell carcinoma

Code Classification

  • Neoplasms (C00–D48)
    • Melanoma and other malignant neoplasms of skin (C43-C44)
      • Merkel cell carcinoma (C4A)

C4A 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. The code is not specific and is NOT valid for the year 2022 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 for Merkel cell carcinoma

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

  • BILLABLE CODE - Use C4A.0 for Merkel cell carcinoma of lip
  • NON-BILLABLE CODE - C4A.1 for Merkel cell carcinoma of eyelid, including canthus
  • BILLABLE CODE - Use C4A.10 for Merkel cell carcinoma of unspecified eyelid, including canthus
  • NON-BILLABLE CODE - C4A.11 for Merkel cell carcinoma of right eyelid, including canthus
  • NON-BILLABLE CODE - C4A.12 for Merkel cell carcinoma of left eyelid, including canthus
  • NON-BILLABLE CODE - C4A.2 for Merkel cell carcinoma of ear and external auricular canal
  • BILLABLE CODE - Use C4A.20 for Merkel cell carcinoma of unspecified ear and external auricular canal
  • BILLABLE CODE - Use C4A.21 for Merkel cell carcinoma of right ear and external auricular canal
  • BILLABLE CODE - Use C4A.22 for Merkel cell carcinoma of left ear and external auricular canal
  • NON-BILLABLE CODE - C4A.3 for Merkel cell carcinoma of other and unspecified parts of face
  • BILLABLE CODE - Use C4A.30 for Merkel cell carcinoma of unspecified part of face
  • BILLABLE CODE - Use C4A.31 for Merkel cell carcinoma of nose
  • BILLABLE CODE - Use C4A.39 for Merkel cell carcinoma of other parts of face
  • BILLABLE CODE - Use C4A.4 for Merkel cell carcinoma of scalp and neck
  • NON-BILLABLE CODE - C4A.5 for Merkel cell carcinoma of trunk
  • BILLABLE CODE - Use C4A.51 for Merkel cell carcinoma of anal skin
  • BILLABLE CODE - Use C4A.52 for Merkel cell carcinoma of skin of breast
  • BILLABLE CODE - Use C4A.59 for Merkel cell carcinoma of other part of trunk
  • NON-BILLABLE CODE - C4A.6 for Merkel cell carcinoma of upper limb, including shoulder
  • BILLABLE CODE - Use C4A.60 for Merkel cell carcinoma of unspecified upper limb, including shoulder
  • BILLABLE CODE - Use C4A.61 for Merkel cell carcinoma of right upper limb, including shoulder
  • BILLABLE CODE - Use C4A.62 for Merkel cell carcinoma of left upper limb, including shoulder
  • NON-BILLABLE CODE - C4A.7 for Merkel cell carcinoma of lower limb, including hip
  • BILLABLE CODE - Use C4A.70 for Merkel cell carcinoma of unspecified lower limb, including hip
  • BILLABLE CODE - Use C4A.71 for Merkel cell carcinoma of right lower limb, including hip
  • BILLABLE CODE - Use C4A.72 for Merkel cell carcinoma of left lower limb, including hip
  • BILLABLE CODE - Use C4A.8 for Merkel cell carcinoma of overlapping sites
  • BILLABLE CODE - Use C4A.9 for Merkel cell carcinoma, unspecified

Clinical Information

Information for Patients


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

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 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 (First year ICD-10-CM implemented into the HIPAA code set)