Carcinoma in situ of skin of lip

This code represents the presence of abnormal, non-invasive epithelial cells confined to the epidermis of the skin of the lip, excluding the vermilion border. These cells show malignant features but have not invaded the underlying dermis. It signifies an early stage of cancer that has not spread.

Assign this code when documentation specifies carcinoma in situ affecting the cutaneous (skin) portion of the lip. This diagnosis is typically confirmed by biopsy showing intraepidermal neoplastic cells without evidence of stromal invasion. Use this code when the pathology report clearly distinguishes the lesion as carcinoma in situ and specifies its location on the skin of the lip.

• Carefully differentiate between carcinoma in situ of the skin of the lip and carcinoma in situ of the vermilion border, which is coded separately.
• Ensure the pathology report explicitly states "in situ" and specifies the lip's skin as the anatomical site.
• Do not use this code for invasive squamous cell carcinoma or basal cell carcinoma of the lip.