Valid for Submission
C4A.21 is a billable diagnosis code used to specify a medical diagnosis of merkel cell carcinoma of right ear and external auricular canal. The code C4A.21 is valid during the fiscal year 2021 from October 01, 2020 through September 30, 2021 for the submission of HIPAA-covered transactions.
Diagnostic Related Groups - MS-DRG Mapping
Convert C4A.21 to ICD-9 Code
The General Equivalency Mapping (GEM) crosswalk indicates an approximate mapping between the ICD-10 code C4A.21 its ICD-9 equivalent. The approximate mapping means there is not an exact match between the ICD-10 code and the ICD-9 code and the mapped code is not a precise representation of the original code.
Information for Patients
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
- Basal cell carcinoma (Medical Encyclopedia)
- Mohs micrographic surgery (Medical Encyclopedia)
- Skin lesion biopsy (Medical Encyclopedia)
- Skin self-exam (Medical Encyclopedia)
- Squamous cell skin cancer (Medical Encyclopedia)