Carcinoma in situ of endometrium

This code signifies the presence of abnormal, pre-invasive cancerous cells confined to the glandular epithelium of the endometrium, the inner lining of the uterus. These cells have not invaded the underlying stromal tissue. It represents the earliest stage of endometrial cancer development.

Apply this code when pathology reports confirm carcinoma in situ of the endometrium, often identified during endometrial biopsy or D&C. Documentation must explicitly state "carcinoma in situ" or "CIS" of the endometrium, without evidence of invasion.

• Distinguish from atypical endometrial hyperplasia, which is a precancerous condition but not yet CIS.
• Do not use if there is any evidence of stromal invasion; in such cases, a malignant neoplasm code would be appropriate.
• Ensure the pathology report clearly specifies the site as endometrium to avoid confusion with CIS of other female genital organs.