DCIS and LCIS: how these breast findings differ

LCIS stands for lobular carcinoma in situ, but classic LCIS is generally treated as a risk marker and non-obligate precursor rather than as invasive cancer. Neither DCIS nor LCIS has crossed the boundary of the structure where it arose.

The words classic, pleomorphic, or florid can materially change the discussion about LCIS. Pleomorphic and florid LCIS may behave differently from classic LCIS and are often managed more actively. The report should also say whether the sample contains DCIS, invasive disease, or another high-risk change.

DCIS is assessed for features such as grade, extent, hormone-receptor status, and clearance at the edge of surgically removed tissue. These details help shape local treatment and possible risk-reducing medication.

After DCIS, the breast team commonly discusses surgery. Breast-conserving surgery may be followed by radiotherapy, while mastectomy can be considered when the area is extensive, appears in separate parts of the breast, or clear tissue edges cannot be achieved.

After classic LCIS, care more often centres on ongoing breast screening, awareness of new breast changes, and an individual risk assessment. Risk-reducing endocrine therapy may be an option for some people. Surgery may be considered for a discordant biopsy result or a non-classic LCIS subtype.

Book an assessment if you notice a new lump in the breast or underarm, spontaneous bloody nipple discharge, new nipple inversion, persistent dimpling, or a lasting change in breast size, contour, or skin. DCIS and LCIS are often detected without a noticeable lump, so attend recommended imaging even when you feel well.

During recovery from biopsy or surgery, seek prompt advice for fever, spreading redness, drainage from the wound, increasing swelling, or pain that is worsening despite the advised medication.

Ask whether the finding is DCIS, classic LCIS, or a non-classic LCIS subtype; whether imaging and pathology agree; and whether the sample was completely removed. Request a clear explanation of the recommended imaging schedule, local treatment choices, medication options, and how your personal and family history affects the plan.