Skin Cancer and Melanoma ICD-10-CM codes

Non-melanoma skin cancer is in category C44, which is organized first by site (C44.0- lip, C44.1- eyelid, C44.2- ear, C44.3- face, C44.4- scalp and neck, C44.5- trunk, C44.6- upper limb, C44.7- lower limb, C44.9- unspecified site) and then by histology in the next character: 1 for basal cell carcinoma, 2 for squamous cell carcinoma, 9 for other specified, and 0 for unspecified type. A further character adds laterality or subsite where applicable; for example C44.311 is basal cell carcinoma of the skin of the nose and C44.612 is basal cell carcinoma of the skin of the left upper limb. C44.91 and C44.92 (basal or squamous cell of unspecified site) should only be used when the site is truly undocumented.

Melanoma is coded to C43 by site with laterality for paired sites (C43.61 right upper limb, C43.72 left lower limb, C43.4 scalp and neck, C43.9 unspecified). Melanoma in situ is D03.- with the same site structure and must not be coded to C43. Merkel cell carcinoma has its own category C4A (C4A.9 unspecified site), and squamous or basal cell carcinoma in situ (Bowen disease) is D04.-. Each separate primary lesion is coded separately, so a patient with a basal cell on the nose and a squamous cell on the ear receives two C44 codes.

Do not code a skin lesion as malignant until pathology confirms it; before the result is available, use the presenting lesion code (for example D48.5 neoplasm of uncertain behavior of skin only when the pathologist states uncertain behavior, or D49.2 when the behavior is not documented, or L98.8 for a lesion not yet characterized). After excision with clear margins and no further treatment, report history codes: Z85.820 for melanoma, Z85.821 for Merkel cell carcinoma, and Z85.828 for other skin malignancies. Z12.83 is the screening code for a skin cancer check in a patient with no lesion.