ICD-10-CM > C00-D49 > C43-C44 > C4A > C4A.1 C4A.1 Merkel cell carcinoma of eyelid, including canthus Non-Billable/Non-Specific Codes C4A.10Merkel cell carcinoma of unspecified eyelid, including canthusC4A.11Merkel cell carcinoma of right eyelid, including canthusC4A.111Merkel cell carcinoma of right upper eyelid, including canthusC4A.112Merkel cell carcinoma of right lower eyelid, including canthusC4A.12Merkel cell carcinoma of left eyelid, including canthusC4A.121Merkel cell carcinoma of left upper eyelid, including canthusC4A.122Merkel cell carcinoma of left lower eyelid, including canthus