Mammary duct ectasia happens when a milk duct beneath the nipple widens and fills with thick, sticky fluid. It is most common in women aged 40–60 and can mimic more serious breast problems, so knowing its typical signs is helpful. The classic first complaint is a sticky, greenish, brown or black nipple discharge that may stain a bra or be noticed only when the nipple is squeezed. The discharge is usually painless and varies from a few drops to a constant moistness. Many women feel a dull, heavy ache or a burning sensation behind the nipple that can radiate into... Learn more