There are two types of nipple discharge—physiologic and pathologic. Physiologic discharge tends to occur only when the nipples are squeezed or the breast is compressed. It can be white, green, or yellow in color. The fluid often comes out of more than one opening on the nipple, and it can involve both breasts.
Physiologic nipple discharge in women, men, transfeminine (male-to-female), or transmasculine (female-to-male) adult individuals of any age is not usually appropriate for imaging tests, as long as routine screening mammograms are up to date.
When nipple discharge comes from one breast, occurs spontaneously without squeezing, or is clear or red in color, it is called “pathologic nipple discharge.” To evaluate pathologic nipple discharge in women aged 30 and over and in adult men of any age, a breast ultrasound or diagnostic mammogram is usually appropriate as the first imaging test. The mammogram may be performed using digital breast tomosynthesis (sometimes called “3-D mammogram”). Breast ultrasound and mammography are complementary tests and may be performed at the same time.
In women with pathologic nipple discharge who are under 30 years old, breast ultrasound is usually appropriate as the first imaging test.
In transfeminine (male-to-female) patients of any age with pathologic discharge, breast ultrasound or diagnostic mammogram is usually appropriate as the first imaging test. The mammogram may be performed using digital breast tomosynthesis. Breast ultrasound and mammography are complementary tests and may be performed at the same time.