C4A.9

Applicable To

• Merkel cell carcinoma of unspecified site

• Merkel cell carcinoma NOS

Approximate Synonyms

• Cancer, merkel tumor

• Merkel cell carcinoma

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.

Details

• C4A.9 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.

• The 2023 edition of ICD-10-CM C4A.9 became effective on October 1, 2022.

• This is the American ICD-10-CM version of C4A.9 – other international versions of ICD-10 C4A.9 may differ.