Dermatopathology of the female breast.

To better define the spectrum of neoplastic and inflammatory diseases that affect female breast skin and the nipple-areola complex, we searched an institutional dermatopathology database and identified 500 specimens of female "breast" (from consecutive records accessioned January 2009-March 2011), 143 specimens of "areola," 124 specimens of "nipple" (records from the latter 2 groups were from patients evaluated June 1992-March 2011), and 500 control specimens of "abdomen" (accessioned January 2010-March 2011). Most specimens obtained from breast skin (76%) represented melanocytic or epithelial proliferations (eg, nevi, seborrheic keratoses, and cysts), as did those from the abdomen, whereas many from the nipple (41%) and areola (60%) were of inflammatory dermatoses. A striking finding was eosinophilic spongiosis (ES) in most areola specimens with spongiotic dermatitis (78%); in contrast, ES was identified in 50% and 31% of spongiotic dermatitis specimens from nipple and breast skin, respectively. ES was associated with a clinical diagnosis of dermatitis in all patients except one (who had pemphigus). Metastatic breast cancer was identified in 28 of 767 specimens (4%), including 6 of 124 (5%) from the nipple. Five of 124 specimens from the nipple (4%) and 1 of 143 from the areola (1%) showed Paget disease. All but one patient with Paget disease showed acantholytic features and none had tissue eosinophils. Abnormalities categorized as complications of radiotherapy, including mild fibrosis and vascular ectasias, morphea, and angiosarcoma, constituted a minority of cases. Our data and the literature indicate that few disorders specifically affect breast skin, but the nipple-areola complex should be approached with a different set of diagnostic considerations.