Appearance

• Breasts tend to be fairly symmetrical in fibroglandular (or nonfat) tissue, but occasionally they differ slightly.
  
  

Feeling

• One breast may feel different or thicker than the other breast, but a person performing a self-exam may not notice any difference.
  
  

Mammogram

• Other than the person themselves, the mammogram is the first device to pick up whether moderate to suspicious asymmetry requires more testing.
  
  

Ultrasound

• Women who have had a mammogram may be referred for an ultrasound, which enables doctors to detect whether any solid masses are causing the asymmetry.
  
  

Biopsy

• If an ultrasound detects solid masses, your doctor will refer you to a specialist who will obtain tissue samples via a core needle biopsy to determine if the mass is benign or malignant.
  
  

Increased risk

• Calcifications, underlying masses, or architectural distortion, which is a change in a breast's shape and structure, indicate a greater probability of malignancy when associated with asymmetric breast tissue.