ICD-10 Code C44.520 – Squamous cell carcinoma of anal skin (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C44.520 – Squamous cell carcinoma of anal skin
What it is
This code identifies a squamous cell carcinoma arising in the skin of the anal area. It is used when the malignant lesion is documented as involving anal skin rather than the anal canal.
Clinical signs
Typical findings include a persistent, enlarging skin lesion near the anus that may be ulcerated, crusted, or bleeding. Clinical features vary; refer to documentation for the exact site and pathology confirmation.
When to use this code
Use C44.520 when the record clearly states squamous cell carcinoma of anal skin or an equivalent diagnosis. You may also use it when pathology or specialist documentation confirms a cutaneous primary lesion in the anal region. Check documentation if the note instead describes anal canal cancer or an unspecified perianal mass.
Do not use for
Do not use this code for squamous cell carcinoma of the anal canal, rectum, or other noncutaneous anorectal sites. If the documentation only says “anal cancer” without skin involvement, check documentation.
Coding tip
Verify the anatomic site carefully; “anal skin” and “anal canal” are coded differently.