Invasive Paget's disease of the male nipple: a case report.

Male mammary Paget's disease (MPD) is extremely rare. Furthermore, MPD with invasion downward into the dermis of the male nipple has been reported rarely. A 56-year-old Japanese man presented with a lump and eczema in the right nipple-areola area. Ultrasonography revealed only a cystic lesion below the right areola. With a diagnosis of MPD with invasion into the dermis associated with ductal carcinoma , mastectomy and sentinel lymph node biopsy were performed. MPD with dermal invasion is extremely rare, and only one male case has been reported in the English literature; therefore, the current case is the second case of male MPD with dermal invasion.