Breast cysts are fluid-filled, epithelial-lined cavities that develop within terminal ducto-lobular units under hormonal influence. They may be solitary or multiple and are most prevalent in perimenopausal women. Symptom intensity correlates with cyst size, tension, and associated inflammation.

1. Cyclic or non-cyclic mastalgia
   A well-localised, dull or throbbing pain that increases during the luteal phase; larger cysts produce constant discomfort unrelated to menses.
2. Palpable, resilient mass
   A smooth, round, mobile lump with distinct borders that may feel fluctuant; tension within the cyst creates a firm “rubber-ball” consistency.
3. Rapid variation in size
   Cysts may enlarge within days and regress spontaneously, distinguishing them from solid tumours that grow progressively.
4. Transillumination
   A discrete, well-circumscribed area of light transmission is visible when examined in a darkened room; this sign is lost when cyst wall calcifies.
5. Nipple discharge
   Clear, serous, or green-brown fluid may be expressed from a single duct; bloody aspirate mandates cytological evaluation to exclude intracystic papilloma or carcinoma.
6. Tenderness to pressure
   Compression against the chest wall or during mammographic paddles elicits sharp pain; spontaneous relief often follows ultrasound-guided aspiration.
7. Axillary discomfort
   Reactive, tender lymph nodes < 1 cm are common; firm or matted nodes require biopsy to exclude concurrent malignancy.
8. Acute inflammatory episode
   Sudden increase in size with erythema and localised heat suggests secondary infection or hemorrhage into the cyst cavity.