Nipple discharge

• Physiologic

o Discharge only with compression o Multiple duct involvement o Bilateral o Fluid may be clear, yellow, white or dark green

• Pathologic

o Spontaneous discharge o Bloody o Unilateral o Associated with a mass

• Physiologic/Endocrinologic Discharge

o Lactation

+ Milk produced in presence of postpartum exocrin, parathyrin, thyroxine, cortisol, growth hormone and placental lactogen + Milk secreted via stimulation of lobular and ductal epithelium by PRL + Milk ejected via stimulation of muscular walls of lactiferous ducts by oxytocin + Oxytocin and PRL secreted by pituitary in response to nipple stimulation

o Galactorrhea:

+ Milk secretion unrelated to pregnancy/lactation + Usually due to hyperprolactin state, though can be idiopathic with normal prolactin (PRL) + Can occur via:

1. Chronic breast stimulation (nipple manipulation, rubbing on bra)
2. Oral Contraceptive Pills (OCPs) – E can stimulate PRL secretion
3. Drugs that inhibit dopamine (loss of tonic inhibition of PRL)
4. Hypothalamic/pituitary disease interfering with DA release
5. Prolactinoma
6. Hypothyroidism
7. Chronic renal failure
8. Chest wall injury – healing wound stimulates PRL release

• Pathologic Discharge

o Intraductal papilloma: monotonous proliferation of papillary cells growing into the lumen

+ Fluid typically straw-colored, transparent, sticky

o Duct ectasia: distention of subareolar ducts o Fibrocystic disease: associated irritation within the duct o Papillomatosis: formation of multiple papillomas

+ Associated with small increase in breast cancer risk

o Intraductal hyperplasia: increased number of epithelial cells lining the ducts

+ Cells appear benign but associated with small increase in breast cancer risk

o Breast cancer: risk much increased if mass associated with abnormal discharge