ICD-10-CM C4A: Merkel cell carcinoma

ICD-10-CM Diagnosis Code (2025)

Official Description for C4A

Merkel cell carcinoma

Coding Notes & Guidelines for C4A

Excludes1: Not Coded Here

malignant neoplasm of vermilion border of lip (C00.0-C00.2)

Excludes2: Not Included Here
  • malignant neoplasm of anus NOS (C21.0)
  • malignant neoplasm of scrotum (C63.2)
Inclusion Terms
  • Merkel cell carcinoma of anal margin
  • Merkel cell carcinoma of perianal skin
Inclusion Terms
  • Merkel cell carcinoma of unspecified site
  • Merkel cell carcinoma NOS

Child Codes (More Specific Codes for C4A):

C4A.0 - Merkel cell carcinoma of lip C4A.1 - Merkel cell carcinoma of eyelid, including canthus C4A.10 - Merkel cell carcinoma of unspecified eyelid, including canthus C4A.11 - Merkel cell carcinoma of right eyelid, including canthus C4A.111 - Merkel cell carcinoma of right upper eyelid, including canthus C4A.112 - Merkel cell carcinoma of right lower eyelid, including canthus C4A.12 - Merkel cell carcinoma of left eyelid, including canthus C4A.121 - Merkel cell carcinoma of left upper eyelid, including canthus C4A.122 - Merkel cell carcinoma of left lower eyelid, including canthus C4A.2 - Merkel cell carcinoma of ear and external auricular canal C4A.20 - Merkel cell carcinoma of unspecified ear and external auricular canal C4A.21 - Merkel cell carcinoma of right ear and external auricular canal C4A.22 - Merkel cell carcinoma of left ear and external auricular canal C4A.3 - Merkel cell carcinoma of other and unspecified parts of face C4A.30 - Merkel cell carcinoma of unspecified part of face C4A.31 - Merkel cell carcinoma of nose C4A.39 - Merkel cell carcinoma of other parts of face C4A.4 - Merkel cell carcinoma of scalp and neck C4A.5 - Merkel cell carcinoma of trunk C4A.51 - Merkel cell carcinoma of anal skin C4A.52 - Merkel cell carcinoma of skin of breast C4A.59 - Merkel cell carcinoma of other part of trunk C4A.6 - Merkel cell carcinoma of upper limb, including shoulder C4A.60 - Merkel cell carcinoma of unspecified upper limb, including shoulder C4A.61 - Merkel cell carcinoma of right upper limb, including shoulder C4A.62 - Merkel cell carcinoma of left upper limb, including shoulder C4A.7 - Merkel cell carcinoma of lower limb, including hip C4A.70 - Merkel cell carcinoma of unspecified lower limb, including hip C4A.71 - Merkel cell carcinoma of right lower limb, including hip C4A.72 - Merkel cell carcinoma of left lower limb, including hip C4A.8 - Merkel cell carcinoma of overlapping sites C4A.9 - Merkel cell carcinoma, unspecified

About ICD-10-CM Code C4A (Merkel cell carcinoma)

ICD-10-CM code C4A is a billable or specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes. The 2025 edition of ICD-10-CM C4A became effective on October 1, 2024.

This page provides detailed information about C4A - Merkel cell carcinoma. It includes common terminology, coding guidelines such as "Includes," "Excludes1," and "Excludes2" notes, and information on required 7th characters. Utilizing this information correctly is essential for accurate medical coding and claims submission for conditions like Merkel cell carcinoma.