At first, invasive lobular carcinoma may not cause any symptoms. Sometimes, an abnormal area turns up on a screening mammogram (X-ray of the breast), which leads to further testing. Invasive lobular carcinomas tend to be more difficult to see on mammograms than invasive ductal carcinomas. That’s because instead of forming a lump, the cancer cells more typically spread to the surrounding connective tissue (stroma) in a line formation.
In other cases, the first sign of ILC is a thickening or hardening in the breast that can be felt, rather than a distinct lump. Other possible symptoms include an area of fullness or swelling, a change in the texture of the skin, or the nipple turning inward.
According to the American Cancer Society, any of the following unusual changes in the breast can be a first sign of breast cancer, including invasive lobular carcinoma:
- swelling of all or part of the breast
- skin irritation or dimpling
- breast pain
- nipple pain
- redness, scaliness, or thickening of the nipple or breast skin
- a nipple discharge other than breast milk
- a lump in the underarm area