Clinical features of MDE:
(1) spontaneous, intermittent nipple discharge (clear, yellow, brown, green) often positive for blood
(2) breast pain
(3) breast lump
(4) nipple inversion or retraction may develop as chronic fibrosis progresses
(5) dilated ducts may be large enough to be palpated through the skin
Pathologic features seen on histologic examination:
(1) dilatation of breast ducts in the subareolar duct system
(2) acute or chronic periductal inflammation that ranges from minimal to marked
(3) periductal fibrosis
(4) ducts may contain amorphous or granular material with or without histiocytes
(5) microcalfications may be present in the luminal contents
(6) the epithelium in the terminal lactiferous ducts may undergo squamous metaplasia, which may be followed by squamous plugging and further duct obstruction
