Invasive Lobular Carcinoma (ILC)


Written by : Dr.M.D.Mazumdar, MD

Invasive Lobular Carcinoma (ILC), also called Infiltrating Lobular Cancer, make up about 10% of all breast cancers diagnosed. After Invasive Ductal Breast Cancer, it is the second most common breast cancer. Invasive means that the cancer which had originally started in the lobules of the breast has broken through the basement membrane of the lobules and invaded the surrounding tissue.

Compared to IDC, ILC tends to be larger in size at the time of diagnosis. It is also more likely to be estrogen and progesterone receptor positive. Spread to the gastrointestinal tract and ovary is also commoner than IDC.


It is common for lobular breast cancer to be diagnosed in both the breasts at the same time. If the condition occurs in only one breast, there is a high risk of it developing in the other breast in time.

Invading cells of ILC tend to break out of the main tumor in single file ('indian style') and spread through the breast in a web like pattern. They do not cause much response from the healthy cells - nether an inflammatory nor a scarring response as is seen in IDC. So a discrete mass or lump is not felt unless the tumor is quite large.

Risk Factors

  • Age : Invasive Lobular Breast Cancer (ILC) can occur at any age but is most common in women above 55 years. It is basically a postmenopausal condition.

  • Sex : ILC can also occur in men of the same age, but is quite rare. Male breast cancers are usually Invasive ductal cancers.
  • Use of HRT : Some research has suggested that the use of hormone replacement therapy during and after menopause can increase the risk of ILC. Researchers have suggested that hormone replacement therapy after menopause may increase the risk of this type of cancer.
  • Inherited genetic cancer syndromes : Women with a rare inherited condition called hereditary diffuse gastric cancer syndrome have an increased risk of both stomach (gastric) cancer and invasive lobular carcinoma.

    Formation of Invasive Lobular Cancer

    Symptoms of Invasive Lobular Carcinoma (ILC):

    • No Symptoms: In early cases, Invasive lobular breast cancer may not cause any symptoms of breast cancer. It may be suspected at a routine mammography or physical examination and then confirmed by a biopsy.

    • No Breast Lump: Unlike most other breast cancers, invasive lobular cancer can occur without the presence of any lumps at all. This is because, it tends to form long, skinny 'fingers' of cancer cells which are much less irritating to the surrounding healthy tissue. These cause less inflammatory reaction in the tissues and so the chances of forming a lump is less.

    • Thickening or Hardening of Breast Tissue: Some women may present with a thickening or hardening of the breast tissue with no specific lump. A change in the texture or 'feeling' of the breast tissue may also be present.

    • Dimpling of the Skin of the Breast: In some cases of invasive lobular breast cancer, the first symptom may be dimpling or irregularities of the skin of the breast or in the nipple. This can occur due to strands of tumor cells pulling on the skin to form dimples.

    • Thickening in the Breast: The layers of cancer cells in lobular invasive cancer can cause thickening in the affected parts of the breast. On palpation, there will appear to be a change in the general texture of the breast with no definite lump felt. This makes lobular invasive cancer very difficult to diagnose on physical examination. Most invasive ductal cancer are first diagnosed when they form a lump of about 2 cm, but invasive lobular cancer can be about 5 cm in size before a diagnosis can be made.

    • Inversion of the Nipple: The nipple may be inverted or retracted inwards when the tumor cells stretch between the nipple and the tumor deeper inside the breast and pull at the nipple.

    • Nipple Discharge: Nipple discharge can occur in later cases when there is concurrent infection. The discharge may be yellowish, greenish or reddish. Reddish implies the presence of blood while greenish or yellowish may indicate the presence of infection.

    • Pain: Pain is very uncommon. But in the presence of infection of the lump or when the lump presses on sensitive tissues like the nerves, there may be some amount of pain. Some women may experience a heaviness or a dull ache in the breast rather than actual pain.

    • Lump under the Armpit: When the cancer cells spread to the lymph nodes under the armpit, hard lumps may be felt in this region.

    • Nipple Irritation, Itching: Redness, scaliness, itching or thickening of the nipple generally occurs when the invasive ductal cancer is very close to or just under the nipples.

    Survival rates for cancer are typically calculated in terms of how many people live at least five years after their diagnosis. The average five-year survival rate for breast cancer is 90 percent and the 10 year survival rate is 83 percent. The stage of the cancer is important when considering survival rates. For instance, if the cancer is only in the breast, the five-year rate of survival is 99 percent. If it has spread to the lymph nodes, the rate decreases to 85 percent.

    Depending on the stage of breast cancer, the general 5-year survival rates for women are: Stage 0 or 1: nearly 100 percent Stage 2: about 93 percent Stage 3: around 72 percent Stage 4: approximately 22 percent

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