Paget’s disease of the breast, which is completely unrelated to Paget’s disease of bone, accounts for 1% to 3% of all breast cancers. Paget’s disease may be either ductal carcinoma in situ (DCIS) or invasive breast cancer, although in situ lesions predominate.
Paget cells are large eosinophilic cells with pale cytoplasm and large atypical nuclei; these should be distinguished from Toker cells, which tend to be small bland cells that can be found in 10% of normal nipples.
Although most series have included small cohorts, mammographically occult underlying cancers have been found in 29% to 100% of cases of Paget’s disease. Preoperative imaging is critical, particularly if breast conservation is desired. If mammography is negative, breast MRI should be considered. However, if biopsy of the nipple demonstrates invasion and mastectomy is the chosen procedure, the findings on breast MRI would unlikely change management.
Breast conservation was previously thought to be contraindicated because of the need to remove the nipple-areolar complex. However, as with other breast cancers, lumpectomy (to include the nipple-areolar complex) is oncologically safe provided negative margins are obtained even if an underlying invasive cancer is present. The patient should be counseled, however, about the resulting cosmetic deformity. Radiotherapy alone is insufficient treatment and has not been evaluated for this disease.
Evaluation of the nodes with use of sentinel lymph node biopsy is indicated in standard fashion if invasive cancer is present, or if the patient opts for a mastectomy and has DCIS.
Bijker N, Rutgers EJ, Duchateau L, et al. Breast-conserving therapy for Paget disease of the nipple: a prospective European Organization for Research and Treatment of Cancer study of 61 patients. Cancer. 2001;91:472-477.
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Echevarria JJ, Lopez-Ruiz JA, Martin D, Imaz I, Martin M. Usefulness of MRI in detecting occult breast cancer associated with Paget’s disease of the nipple-areolar complex. Br J Radiol. 2004;77:1036-1039.
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