Breast cancer is the most common cancer in women and scientists are saying that a “lump” isn’t the only sign of the disease.

While breast cancer is more survivable than other variations of the disease, the society also projects over 42,000 deaths from breast cancer. In total, there are 321,000 cases expected in the U.S. this year, according to the American Cancer Society. To ensure patients catch the cancer before the disease spreads too much, doctors say there are several symptoms for women to look out for.

But one is particularly concerning – and it isn’t a lump, a hallmark of breast cancer.

It’s dimpling, or an orange peel-like appearance of the skin of the breast. The symptom is “almost always breast cancer,” Dr. Tara Olson, an OB-GYN at the Maryland-based Simmonds, Martin & Helmbrecht women’s health clinic, told Prevention over the weekend.

That’s because the skin changes are typically tied to the rare and aggressive inflammatory breast cancer.

There are many different types of breast cancer, but inflammatory breast cancer cases make up only 1 to 5 percent of all breast cancer cases, according to the National Institutes of Health.

Most cases start in cells that line the milk ducts of the breast and then spread beyond to nearby tissue. This type of breast cancer does not typically lead to lumps, which medical professionals have long said is a sign that women might need to seek care.

Instead of a lump, inflammatory breast cancer changes the color of the skin of the breast, causing it to appear bruised, red, pink and purple. It may also lead to an increase in breast size, heaviness, burning or tenderness of the breast, a nipple that inverts itself and swollen lymph nodes under the arm or near the collarbone, the NIH says.

It also doesn’t usually appear on a screening mammogram, the M.D. Anderson Cancer Center notes, which is why it is often misdiagnosed.

Inflammatory breast cancers are known to develop and progress within just weeks to a couple of months, according to Yale Medicine, making early detection crucial.

“In general, inflammatory breast cancer has a poorer prognosis than do most other types of breast cancer,” the medical school warns.

Some people are at a higher risk for inflammatory breast cancer including women living with obesity, Black women and younger adults, Northwestern Medicine says.

Beyond a physical examination at home, women should seek out a doctor for imaging tests or a biopsy of breast tissue.

Inflammatory breast cancer can be treated with chemotherapy and drugs before surgery is needed. Earlier cases can be cured, though the cancer is “always considered at least stage III,” according to the M.D. Anderson Cancer Center.

“So, the sooner you can diagnose it and start treatment before it progresses to stage IV, the better chance you have of a cure,” the center notes.

After stage IV, the cancer can be treated but not cured.