Kylie Armstrong's Facebook post caught the attention of women worldwide after she said a picture, showing three faint dimples on the bottom of her breast, turned her life upside down.
Armstrong, who lives in Melbourne, Australia, wrote, "This is what my breast cancer looks like. I felt no lump. The GP felt no lump."
In breast cancer, skin dimpling can occur when a cancerous tumor grows, and it draws the skin in. Sometimes the tumor can be so deep the patient can't feel it.
In Armstrong's case, an ultrasound determined the tumor was located far inside her breast, close to her pectoral muscle.
"The reality is breast cancer can present in some very unusual ways," Dr. Deanna Attai, the president of the American Society of Breast Surgeons, said.
Attai said while a lump may be the most common indicator of breast cancer, it's not the only the sign.
"It does stress the importance that women be aware of even minor changes in their breast," Attai said. "Get a sense of what their normal is because subtle changes like this could indicate breast cancer."
Other changes to watch out for include rash, redness, inflammation that won't go away with antibiotics and inverted nipples that can't be moved back.
"If something doesn't seem right to you, make sure you see your doctor and get it evaluated," Attai said.
On her page, Armstrong wrote, "I am sharing this because I hope I can make people aware that breast cancer is not always a detectable lump."
Armstrong is recovering well from her surgery and said she's grateful for the incredible number of warm wishes she received. She added she's touched that many women decided to get checked after hearing about her story.