Aetiology

Physiological

• During breast feeding

Galactorrhoea

• Commonest cause may be response to emotional events, drugs such as histamine receptor antagonists are also implicated

Hyperprolactinaemia

• Commonest type of pituitary tumour
• Microadenomas <1cm in diameter
• Macroadenomas >1cm in diameter
• Pressure on optic chiasm may cause bitemporal hemianopia

Mammary duct ectasia

• Dilatation breast ducts
• Most common in menopausal women
• Discharge typically thick and green in colour
• Most common in smokers

Carcinoma

• Often blood stained
• May be underlying mass or axillary lymphadenopathy

Intraductal papilloma

• Commoner in younger patients