ICD-10 Code C44.81 – Basal cell carcinoma of overlapping sites of skin (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C44.81 – Basal cell carcinoma of overlapping sites of skin
What it is
C44.81 identifies basal cell carcinoma arising in overlapping skin sites, meaning the tumor spans more than one adjacent anatomic area and no single site is documented. Use this code when the record clearly supports basal cell carcinoma but not a more specific location.
Clinical signs
Typical findings include a slow-growing skin lesion that may be pearly, translucent, ulcerated, or crusted. Clinical features vary; refer to documentation, especially when pathology confirms basal cell carcinoma and the lesion crosses overlapping sites.
When to use this code
Use C44.81 when the provider documents basal cell carcinoma involving overlapping skin regions, such as a lesion extending across adjacent borders and no single site is assigned. It also fits when pathology or the assessment names overlapping sites rather than one precise skin location. If the note gives a specific anatomic site, code that site instead.
Do not use for
Do not use this code for squamous cell carcinoma, melanoma, or benign skin lesions. Also avoid it when documentation identifies one exact skin site or when the chart only says “skin cancer” without confirming basal cell carcinoma.
Coding tip
Check the operative note, pathology, and assessment for the exact site wording before choosing an overlapping-site code.