When Michelle Forney’s breast started swelling and itching, doctors told her she had mastitis, a common infection, and treated her with antibiotics. When she discovered that she, in fact, had a rare form of lymphoma and that it was probably caused by her breast implant, she was both furious and frightened.

Forney is just one of hundreds of breast-implant recipients who have developed a rare blood cancer called anaplastic large cell lymphoma (ALCL). The Food and Drug Administration has been investigating reports linking breast implants with the cancer, and now has more than 400 reports about patients who developed ALCL after having a breast implant, including nine who died.

“I had my breast implants for about 19 years. And everything was fine for many of those years until about three years ago,” when she developed major itching and pain in her breast, said Forney, who is 46 and lives in Sacramento.

“Come December of last year, I woke up one day and my breast was the size of a volleyball. Within a day it grew and just engorged,” Forney told NBC News. “So I immediately went back to the doctor, saw my OB-GYN and she brought in a breast specialist. And they said: ‘Oh, breast mastitis. You have an infection.’”

But a 10-day course of antibiotics did nothing to help.

Forney’s doctors did not link the symptoms to lymphoma, she said, and mammograms showed no problem. It took several more visits to determine she had lymphoma. Finally, after a plastic surgeon persuaded Forney to have her implants removed, dozens of tiny tumors were found around the implant.

Women choose to get breast implants either for breast reconstruction after mastectomy or for cosmetic reasons. The American Society of Plastic Surgeons reported 400,000 breast implant procedures took place in 2017, up nearly 40 percent since 2000.

Image: Michelle Forney
Michelle Forney, right, with her friend, Camme Iannelli, in January 2000. Forney, now 41, was diagnosed with a cancer of the immune system earlier this year. Courtesy of Michelle Forney

It’s taken several years to gather data but the FDA now believes that textured breast implants may be more likely to cause ALCL, although it says smooth implants are also linked to an increased risk. The trouble is that there’s no organized effort to put together data from people who have implants and those who have developed ALCL.

For more on this story, watch NBC Nightly News with Lester Holt on Monday evening. The NBC News series on “Medical Device Dangers” continues Tuesday morning on TODAY.

“Many studies have looked to estimate risk and, depending on the source data and country, the global lifetime risk of developing breast-implant-associated ALCL for patients with textured breast implants ranges anywhere from 1 in 3,817 to 1 in 30,000,” the FDA said.

New data from Australia indicates as many as one in 1,000 people with breast implants may develop ALCL. The FDA said the implants available in Australia are different from those sold in the U.S., and that complicates efforts to figure out the true risks.

The FDA is holding public hearings on the issue next year to try to find out more about the potential links, and to ask people what should be done about it. So is the French government, and France’s national health authority is in the meantime recommending against the use of textured implants.

“One of the problems in the United States is … with patients going to different doctors at different times and the doctors aren’t necessarily communicating with each other and their medical records aren’t communicating with each other,” said Dr. Diana Zuckerman, president of the National Center for Health Research, a nonprofit, nonpartisan advocacy organization based in Washington. “There’s really no way to know when women with breast implants get any number of health problems, including cancer.”