Characterization

Breast cysts are best characterized on ultrasound. On mammography, a breast cyst appears as a round, circumscribed mass (i.e., indistinguishable from a solid breast mass).

• Asymptomatic cysts: no intervention required; most resolve spontaneously

• Symptomatic cysts : Consider ultrasound-guided fine needle aspiration.

  • Simple cysts generally collapse on aspiration.

  • Aspirate is typically serous and can be discarded.

Simple breast cysts are not associated with an increased risk of breast cancer. Routine breast cancer screening is appropriate

Management depends on patient preferences and clinical concern for malignancy and includes the following.

• Surveillance: close clinical and imaging follow-up over 1–2 years

• Therapeutic fine needle aspiration: Any bloody aspirate should be sent for cytology.

• Core needle biopsy is indicated if there is clinical suspicion for malignancy, such as:

  • Lesion persists after aspiration

  • Bloody aspirate obtained

  • Increasing cyst size (on surveillance)

Perform an ultrasound-guided core needle biopsy or excisional biopsy in all patients

• Benign lesion on biopsy [7]

  • Follow-up at 6 and/or 12 months for 1 year.

  • No growth on surveillance: Routine breast cancer screening is appropriate.

• Indeterminate lesion or radio-pathological discordance: surgical excision