Unspecified type of carcinoma in situ of left breast

This code signifies the presence of non-invasive malignant epithelial cells confined to the ducts or lobules of the left breast, without evidence of stromal invasion. It represents an early stage of breast cancer where the abnormal cells have not spread beyond their original location.

Apply this code when documentation confirms carcinoma in situ of the left breast, but the specific histological type (e.g., ductal, lobular) is not specified by the pathologist. This is appropriate for pathology reports indicating "carcinoma in situ, NOS" or "unspecified carcinoma in situ" of the left breast.

• Do not use if the specific type of carcinoma in situ (e.g., D05.12 for lobular, D05.02 for ductal) is documented.
• Ensure the laterality (left breast) is clearly stated in the pathology report.
• This code is typically a primary diagnosis for initial treatment of carcinoma in situ.