Asymmetry in breast size

Last revised by Andrew Murphy on 23 Mar 2023

Asymmetry in breast size can arise from a number of factors.


Breasts are rarely absolutely the same size or volume. Normal variation is common. Most females have slight discrepancies in breast size. Asymmetric progressive breast enlargement is unusual but known. The role of the breast imaging is to exclude an underlying pathology.

Physiological changes occur at puberty in both genders. Asymmetry in males is usually as a result of gynecomastia.

  • developing occult malignancy
  • normal variant
  • post radiation hypoplasia of the breast 2
  • post surgical breast: lumpectomy on the smaller side
  • previous chest wall trauma
  • congenital 
  • Poland syndrome

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Cases and figures

  • Case 1
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  • Case 2: Poland syndrome
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  • Case 3: Poland syndrome
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