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 are. 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