Hi Bobbi: Paget’s disease (its full name is Paget’s disease of the nipple) accounts for fewer than 5% of all breast cancers. It usually occurs in older women; the average age for a woman with Paget’s is 62. But thankfully, its treatment success rate is comparable to that of the majority of breast cancers. (By the way, Paget is Sir James Paget, a 19th-century British physician who was the first to notice the association between changes in the nipple and underlying breast cancer.) Paget’s disease is characterized by itching, scaliness, redness, or oozing of the nipple. This can be very mild at first; in fact, many women with Paget’s are initially treated for eczema. 97% of women with Paget’s disease are found to have underlying invasive breast cancer or DCIS, so it’s presumed that it’s an offshoot of those cancers. (In the 3% of women without DCIS, it’s theorized that cells in the nipple just spontaneously become Paget cells.)   The treatment depends on what kind of cancer is discovered in your breast (assuming your daughter is in the 97% of women whose Paget’s disease stems from an underlying breast cancer). Her treatment will be for the breast cancer she has aside from Paget’s: typically, DCIS, LCIS, IDC, or ILC. In addition, no matter what other type of breast cancer she has, her nipple and areola (the darker area around the actual nipple) will be removed. This gets rid of the Paget cells; she's basically having a tiny little “nipple mastectomy.” If she’s having a lumpectomy–i.e., she’ll be keeping your breast–have her ask the doctor about reconstructive nipple surgery. Hey, if insurance covers it, why not, right?   As for how a needle biopsy can determine stage - I guess it can, otherwise why would he tell her the stage? Perhaps because the nipple is such a small area, that's the only type of biopsy they do.   Hope this helps - PJH