Carcinoma in situ of hard palate

This code signifies the presence of abnormal, non-invasive epithelial cells confined to the hard palate, exhibiting features of malignancy but without invasion through the basement membrane. It represents an early stage of cancer, also known as squamous cell carcinoma in situ, limited to the mucosal surface of the hard palate.

Apply this code when pathology reports confirm carcinoma in situ specifically located on the hard palate. Documentation should clearly state "carcinoma in situ," "CIS," or "intraepithelial neoplasia grade III" of the hard palate, without evidence of stromal invasion.

• Differentiate from invasive squamous cell carcinoma of the hard palate (C05.0) which indicates invasion beyond the basement membrane.
• Ensure the documentation explicitly specifies "hard palate" to avoid confusion with other oral cavity sites.
• Do not use if the lesion is described as dysplasia or atypical hyperplasia without a definitive diagnosis of carcinoma in situ.