Accessory Breast Tissue on Ultrasound

IMAGING FINDINGS: ​

Sonographic image of a palpable area of concern in the left axilla demonstrates normal dense fibroglandular tissue consistent with prominent accessory breast tissue. 
 
WHY IT MATTERS:

1. At least 6% of the population has accessory breast tissue in their axilla. It frequently presents as a palpable axillary lump. Any pathologic process that occurs in the breast can also occur in the accessory tissue.
   
2. Radiologists should be able to recognize the imaging appearance of this normal variant on mammography and ultrasound.
   

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FURTHER READING:
The ABCs of Accessory Breast Tissue: Basic Information Every Radiologist Should Know (AJR 2014)