Carcinoma in situ of skin of ear and external auditory canal

This code signifies the presence of abnormal, non-invasive epithelial cells confined to the epidermis of the skin covering the ear or within the external auditory canal. These cells have the potential to become invasive cancer but have not yet breached the basement membrane. It represents a pre-malignant condition.

This code is appropriate when pathology reports confirm carcinoma in situ affecting the skin of the auricle, helix, lobule, or the lining of the external auditory meatus. Documentation should clearly state "carcinoma in situ," "intraepidermal carcinoma," or "Bowen's disease" of these specific anatomical sites.

• Ensure the pathology report explicitly states "in situ" to differentiate from invasive carcinoma.
• Do not use this code for melanoma in situ; a different code series applies for melanomas.
• Verify the exact anatomical site (ear vs. other skin sites) to ensure correct code selection within the 232 series.