There is a rare and unusual cancer associated with breast implants and it is known as ALCL. Among women with implants, it is extremely rare, with an incidence somewhere around 2 cases per million. For unknown reasons, ALCL tends to be associated only with implants that have a textured surface. When ALCL occurs, in the majority of cases, it does not behave like cancer as it is "cured" by simply removing the scar tissue around the implant.  This behavior leads some scientists to think that ALCL is not really a cancer, but rather an infection that looks like a cancer.  Unfortunately, in 9 patients, it appears that their ALCL really did behave like cancer. 

Most frequently, the first symptom of ALCL is an accumulation of fluid around the breast implant causing swelling of the woman's breast. So patients with significant swelling around their implants, even years after their surgery, should see a plastic surgeon for evaluation. Fortunately, very, very few women who develop this swelling will be found to have ALCL. 

The FDA recommends that patients who currently have implants should simply observe their breasts for swelling or masses;  implant removal is not recommended. Learn more from the FDA's website.