Lobular Breast Cancer

Lobular breast cancer is a distinct subtype of breast cancer.

Invasive Lobular cancer (ILC) has specific molecular features distinct from ductal breast cancer. with its own uniques subtypes and variants. Lobular presents differently in the breast.

Invasive ductal carcinoma (IDC) begins in the milk ducts whereas invasive locular begins in lobules (the milk producing glands of the breast).

A hallmark feature of classical invasive lobular breast cancers is that tumors form in single-file strands rather than the more common “lump” seen in invasive ductile breast cancers.

ILC has differences in presentation and behavior symptoms that can include hardening of the breast, swelling, changes in the appearance of the breast, nipple skin changes or breast pain.

How Is Lobular Breast cancer diagnosed?

Current imaging tools are less reliable for early detection of lobular disease and detection of distance recurrence. ILC is often not seen in routine mammogram or other screening.

ILC tumors can be more difficult to identify on imaging studies and by physical exam because many lack the protein called e-cadherin, which causes an unusual linear growth pattern and not lumps.

If it’s found by palpating the breast, it is more likely to resemble a fullness or thickening in one area. On a mammogram, ILS often appears as an area of distortion.

The diagnosis is confirmed by extracting a small piece of the abnormal tissue with a needle and existing it under a microscope.


ILC has generally been treated like HR-positive invasive ductal carcinoma. Treatments may include: surgery, radiation therapy, chemotherapy or hormonal therapy.

There is increasing evidence that standard of care chemotherapy and endocrine therapies currently equally applied to breast cancer patients may have different effectiveness as applied to ILC and IDC (Invasive Ductal Carcinoma).

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