Simple breast cyst

Case contribution: Dr Radhiana Hassan


  • A 43-year old lady
  • No known medical illness
  • Left breast lump felt for few months
  • Sudden increase in size for the past 2 months
  • No family history of breast cancer
  • No fever, not painful, no nipple discharge
Bilateral mammogram
Bilateral mammogram

Mammogram findings:

  • Bilaterally dense breasts
  • A well-defined mass lesion is seen at left inner midquadrant (yellow arrows)
  • The lesion measures 37×34 mm
  • No stromal distortion or clustered microcalcifications
  • No nipple retraction or skin thickening
Ultrasound breast

Ultrasound finding:

  • A well defined hypoechoic lesion in Lt11H measuring 33x26x13 mm
  • Posterior enhancement seen
  • No internal echoes or debri
  • No abnormal vascularity seen

Progress of patient:

  • FNAC done at pathology lab
  • Yellowish colour aspirate. Lesion totally collapsed after procedure. Hypocellular aspirates with occasional macrophages
  • Impression: benign cysts with apocrine change

Diagnosis: Simple breast cyst


  • Cystic lesions of the breast are common in women between 30-50 years old
  • On mammography, a cystic lesion appears as a round, oval, or lobulated mass with circumscribed margins
  • Mammogram alone cannot reliably diagnosed a cyst
  • Ultrasound reliably differentiate cystic from solid lesions in most cases and permits further characterization of the mass; evaluation of the lesion’s shape, orientation, margin, boundary, internal echotexture, posterior acoustic features, surrounding tissue, calcifications, and vascularity.
  • Simple cysts on ultrasound is seen as an anechoic, well circumscribed with a thin echogenic capsule, increased through-transmission, and thin edge shadows.
  • Simple cyst should not increase in size in post-menopausal women.
  • A simple cyst is classified as BI-RADS 2 and the subsequent follow up follows a screening protocol.
  • Symptomatic large cysts may warrant aspiration. Simple cyst aspiration showing straw colored fluid can be discarded. Cytological analysis is usually not required, unless it contains bloody material.
  • Post-aspiration ultrasound confirms the cyst has disappeared completely with no residual mass and will confirm hemostasis.
  • Complications from aspiration are virtually unknown but include bleeding and theoretically infection.
  • Aspiration of cysts can be safely performed without stopping aspirin therapy.


  • Hines et al. Cysts masses of the breast. AJR 2010: 194:W122-W133
  • Kabbani et al. Simple breast cyst. Radiopedia at
Author: radhianahassan