C4A.10 - Merkel cell carcinoma of unspecified eyelid, including canthus

Version 2023
ICD-10:C4A.10
Short Description:Merkel cell carcinoma of unsp eyelid, including canthus
Long Description:Merkel cell carcinoma of unspecified eyelid, including canthus
Status: Valid for Submission
Version:ICD-10-CM 2023
Code Classification:
  • Neoplasms (C00–D48)
    • Melanoma and other malignant neoplasms of skin (C43-C44)
      • Merkel cell carcinoma (C4A)

C4A.10 is a billable ICD-10 code used to specify a medical diagnosis of merkel cell carcinoma of unspecified eyelid, including canthus. The code is valid during the fiscal year 2023 from October 01, 2022 through September 30, 2023 for the submission of HIPAA-covered transactions.

Unspecified diagnosis codes like C4A.10 are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

Convert to ICD-9 Code

Source ICD-10 CodeTarget ICD-9 Code
C4A.10209.31 - Merkel cell ca-face
Approximate Flag - The approximate mapping means there is not an exact match between the ICD-10 and ICD-9 codes and the mapped code is not a precise representation of the original code.

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 :

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