You listen to your doctor and read the news about breast cancer. You check for lumps, go for mammograms and think you are on top of it. But what if there was a breast cancer that struck younger women, didn't cause a lump and might not show up on a mammogram?

There is.

Inflammatory breast cancer (IBC) is one of the rarer types of the disease (less than 5 percent of cases), but it is extremely aggressive and can be mistaken for a simple breast infection. In fact, IBC's ability to sneak up on a person undetected is one of its most insidious traits. And just because you are checking for the traditional signs of breast cancer doesn't mean you will necessarily spot it. In symptoms and treatment, IBC proves to be an exception to many of the "rules" of breast cancer:

1.  Breast cancer always has a lump. IBC often does not produce a lump. It occurs in the lymphatic vessels in the breast, where tumor cells block the vessels and cause swelling. The breast may appear warm, swollen and discolored, and larger than the other breast. The skin may be thickened or have the texture of an orange peel. The nipple may be flattened or inverted. IBC can develop quickly, sometimes within weeks, and is sometimes mistaken for a breast infection called mastitis.
   
   
2. Mammograms find all breast cancer. IBC may not be detectable by mammogram or even ultrasound. The tumors are diffuse, spread through the vessels in the breast. And the increase in density of breast tissue that it causes may make the tumor cells difficult to distinguish on a mammogram.
   
   
3. Breast cancer occurs in older women. The average age for a breast cancer diagnosis is 66. For IBC, one study found that the majority of women are diagnosed between ages 40 and 59. Some women are diagnosed during or shortly after pregnancy, and are often shocked to realize that the changes occurring in their breast were not pregnancy-related, but cancer.
   
   
4. Breast cancer has a very high survival rate. Overall, women with breast cancer have an 89 percent five-year survival rate, which includes stage I localized cancer (98 percent) and stage IV distant spread to other organs (27 percent). By its definition, IBC has spread to local tissue around the breast, which means it is automatically at least stage IIIB at diagnosis, and may be stage IV. For IBC, the five-year survival rate is between 25 and 50 percent, according to the National Cancer Institute (NCI). One study published by the NCI showed the average survival time of about three years.

Like other breast cancers, IBC can be diagnosed with a biopsy. Because of its aggressive spread, treatment protocols for IBC are equally aggressive and sometimes more involved than other cases of breast cancer. A typical course of treatment for early-stage breast cancer includes lumpectomy followed by a course of radiation, possibly followed by hormonal therapy. However, women with IBC usually receive chemotherapy before surgery to shrink the tumor for surgery. After surgery, treatment continues with radiation to the chest wall, and possibly more chemo or hormonal therapy, depending on the characteristics of the tumor. Although the survival rates are still lower than for other types of breast cancer, they have improved recently as researchers have learned more about tumor characteristics and which therapies work best.

The bottom line for IBC: Pay attention to changes in your breasts:

1.  Know if something is unusual for you: a change in size or color.
   
   
2. Pay special attention if you are pregnant. The hormonal changes of pregnancy contribute to many breast changes and can sometimes mask the development of IBC.
   
   
3. Always consult your doctor about any unusual symptoms. If you are treated for a breast infection and see no changes after a week, go back and continue the search.
   

Though it's important to be aware of possible IBC symptoms, remember that it is rare and most other breast cancers are still identified through mammograms. So continue to get regular mammograms.