(USA TODAY) -- No one knew what to make of Terry Arnold's right breast.

By the time she was 49, the breast suddenly became red, hot and swollen. "I thought something bit me," says Arnold, of Friendswood, Texas. Her doctor, who diagnosed her with a pituitary gland infection, prescribed eight weeks of antibiotics.

They didn't help.

Arnold's breast swelled from a C to a D cup. "I had to buy a new bra and pad my clothes to even them out," she says.

Months went by, and Arnold saw five doctors. Some of their explanations were stranger than others.

"One doctor said, 'You have menopause in one breast,'" Arnold says.

Eventually, Arnold arrived at Houston's M.D. Anderson Cancer Center, where she learned she had inflammatory breast cancer, or IBC, the most aggressive form of the disease. IBC takes its name from the red inflammation it produces in the breast, which is caused when microscopic tumor cells clog lymph vessels.

Like most women diagnosed with IBC, Arnold had never even heard of it. Today she tells her story often, to educate women and doctors about a tumor that few recognize and to raise money for an "orphan disease" that gets relatively few research dollars.

Although these tumors are rare -- accounting for only about 4% of breast cancer cases -- they are often lethal: They cause perhaps 10% of the 39,500 annual deaths from breast cancer in the USA, says Naoto Ueno, executive director of M.D. Anderson Cancer Center's inflammatory breast cancer research program and clinic. The median survival for women with IBC is less than three years, says Massimo Cristofanilli, chairman of medical oncology at Fox Chase Cancer Center in Philadelphia and a leading expert on inflammatory breast cancer. Thirty-five percent to 40% of patients have metastases to other organs when they're diagnosed, says Cristofanilli, who was Arnold's doctor at M.D. Anderson.

"They weren't sure whether to take me on as a patient or prepare me for hospice," Arnold says. "They weren't sure they could stop it before it got to my brain."

Patients often are diagnosed late, partly because their family doctors aren't familiar with IBC, Cristofanilli says. And doctors today have no good way to detect IBC early. Unlike most breast cancers, IBC doesn't form a lump that's detectable on mammograms, Cristofanilli says.

Yet even women who are diagnosed soon after symptoms develop say an IBC diagnosis can be devastating. "You're told the bad news twice," says Sachi Mallach, 39, of West Chester, Pa., who was diagnosed two years ago, shortly after suffering a miscarriage. "You're told you have breast cancer. Then, less than a week later, I heard that not only do you have breast cancer, but you have the really aggressive breast cancer."

Because inflammatory cancers often come back, frequently spreading to the chest wall, many doctors advise against implants for fear that they could hide early signs of a recurrence. Arnold notes that patients and doctors are reluctant to use the word "cured" with a disease this aggressive.

"I don't see myself as a cancer survivor," says Arnold, now 54, whose tests are clear of disease. "I am surviving."

Arnold says she wants to help other women and stimulate research. So she reaches out through Facebook, where she has connected with hundreds of women around the world.

Many women with IBC are too sick to attend real support groups; others simply can't find anyone else with their type of breast cancer. Last year, Arnold founded the IBC Network Foundation, a non-profit that raises awareness and money for research.

The group holds Hunt for Hope scavenger hunts in cities across the country. So far, the foundation has given $32,000 to M.D. Anderson to study a common lung complication in IBC.

That may not sound like much, given that cancer trials often cost millions of dollars. But Ueno says even modest donations are important for an "orphan disease" that affects too few patients to attract much attention from pharmaceutical companies.

Yet Cristofanilli says that in some ways, research into inflammatory breast cancer is more promising today than in a long time. That's because of research suggesting that a newly approved lung cancer drug might benefit some women with IBC. The drug, crizotinib, was approved last year to treat late-stage lung cancer patients with a mutation in a gene called ALK. Because some women with IBC have these mutations, scientists are running clinical trials to see whether the drug could help control their disease, too, Cristofanilli says.

Women with IBC, he notes, tend to be several years younger than the average breast cancer patient, and many are raising families. Many are African American. And because IBC is more common among women who are overweight or obese, Cristofanilli says, he's concerned it could become more common. "It affects a part of the population that is very active," Cristofanilli says. "These families are left without their wives, without their mothers. This particular group of women deserves better."

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