2024 ICD-10-CM Diagnosis Code C4A

by

Merkel cell carcinoma

  • C4A should not be used for reimbursement purposes as there are multiple codes below it that contain a greater level of detail.
  • The 2024 edition of ICD-10-CM C4A became effective on October 1, 2023.
  • This is the American ICD-10-CM version of C4A – other international versions of ICD-10 C4A may differ.

The following code(s) above C4A contain annotation back-references

 that may be applicable to C4A:

Clinical Information

  • A carcinoma arising from merkel cells located in the basal layer of the epidermis and occurring most commonly as a primary neuroendocrine carcinoma of the skin. Merkel cells are tactile cells of neuroectodermal origin and histologically show neurosecretory granules. The skin of the head and neck are a common site of merkel cell carcinoma, occurring generally in elderly patients. (holland et al., cancer medicine, 3d ed, p1245)
  • A rare malignant cutaneous tumor seen in elderly patients. Its usual location is on the head, neck and extremities. The tumor is composed of small round cells with scanty cytoplasm arranged in a trabecular pattern, or in ill-defined nodules or in a diffuse pattern. The tumor cells contain cytoplasmic membrane-bound dense core granules resembling neurosecretory granules.
  • A rare type of cancer that forms on or just beneath the skin, usually in parts of the body that have been exposed to the sun. It is most common in older people and in people with weakened immune systems.

Code History

  • 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
  • 2017 (effective 10/1/2016): No change
  • 2018 (effective 10/1/2017): No change
  • 2019 (effective 10/1/2018): No change
  • 2020 (effective 10/1/2019): No change
  • 2021 (effective 10/1/2020): No change
  • 2022 (effective 10/1/2021): No change
  • 2023 (effective 10/1/2022): No change
  • 2024 (effective 10/1/2023): No change

Code annotations containing back-references to C4A: