Mammary and Extramammary Paget's Disease Presented Different Expression Pattern of Steroid Hormone Receptors

BACKGROUND AND OBJECTIVES Paget's disease (PD) is a rare intraepithelial adenocarcinoma, which is composed of mammary (MPD) and extramammary Paget's disease (EMPD). Currently, the published literature contains scant data on expression pattern of steroid hormone receptors in MPD and EMPD. METHODS Expression of estrogen receptor (ER) and androgen receptor (AR) was evaluated in 88 MPD and 72 EMPD by using immunohistochemical staining and H-score method. RESULTS Positive expression of AR was significantly higher in EMPD (61.11%, 44/72) than in MPD (32.95%, 29/88) (P < 0.001), while ER expression was positive 19.44% (14/72) in EMPD and only 9.09% (8/88) in MPD (P = 0.059). ER-AR expression pattern was significantly different between MPD (3.41%, 3/88) and EMPD (16.67%, 12/72) (P < 0.001). No difference of AR (P = 0.301) or ER (P = 0.239) expression was identified between invasive (48.57%, 51/105 of AR, and 11.43%, 12/105 of ER) and noninvasive PD. In MPD, no difference of AR expression between MPD alone (7/18, 38.89%) and MPD with underling ductal carcinoma of breast (22/70, 31.43%) was identified (P = 0.548). In EMPD, expression of AR was 63.33% (38/60) in penoscrotal EMPD. CONCLUSION Our current results indicate that MPD and EMPD presented different expression pattern of AR and ER and would help to further identify the molecular subtype of MPD and EMPD for adjuvant hormonal therapy, especially for patients with penoscrotal EMPD.