Basal cell carcinoma of anal skin

This code identifies a malignant neoplasm originating from the basal cells of the epidermis, specifically located on the skin of the anus. Basal cell carcinoma is the most common type of skin cancer, characterized by slow growth and rare metastasis, but can be locally destructive if left untreated.

Apply this code when documentation confirms a diagnosis of basal cell carcinoma affecting the perianal or anal canal skin. This diagnosis is typically established through biopsy and histopathological examination. Supporting documentation should clearly specify the tumor type and its precise anatomical location.

• Ensure documentation explicitly states "basal cell carcinoma" and "anal skin" or "perianal skin."
• Do not confuse with squamous cell carcinoma or melanoma of the anal region, which have different code assignments.
• Always sequence this code as the primary diagnosis when it is the reason for the encounter (e.g., for excision, biopsy, or treatment).