Epithelial lined fluid-filled cavities, which form when lobules become distended due to blockage, usually in the perimenopausal age group

Aetiology

• Commonly occur during the late reproductive years of a woman’s life

Clinical features

• Can present singularly or with multiple lumps and can affect one or both breasts
• A cyst is typically palpable, clearly defined, soft, mobile, and smooth, with distinct borders
• Cysts are often somewhat tender, especially before menstruation

Investigations

• Mammography: cysts can be identified by their typical halo shape
• Ultrasound: usually provides definitive diagnosis
• Persisting, symptomatic, or undeterminable cystic masses may be aspirated
  • Cancer may be excluded if the fluid is free of blood or the lump disappears, otherwise the cystic fluid should be sent for cytology

Management

• Once diagnosed, cysts usually require no further management and self-resolve, however women are at a higher risk of these recurring
• Larger cysts can be aspirated for aesthetic reasons or patient reassurance