Lobular carcinoma in situ of unspecified breast

This code represents a non-invasive breast condition where abnormal cells are found within the lobules (milk-producing glands) of the breast but have not spread beyond them. It is considered a marker for increased breast cancer risk rather than an invasive cancer itself. The "unspecified breast" designation indicates that the laterality (left or right) of the affected breast is not documented.

Use this code when documentation clearly states a diagnosis of lobular carcinoma in situ (LCIS) without specifying laterality. This diagnosis is typically made following a breast biopsy. Supporting documentation should include pathology reports confirming the presence of LCIS.

• Do not use this code if the laterality (left or right breast) is specified; instead, use the more specific codes D05.01 or D05.02.
• This code is for in situ carcinoma; do not use it for invasive lobular carcinoma.
• LCIS is often an incidental finding and may not be the primary reason for the encounter, but it should always be coded when documented.