Presentation and Presenting Images

( ▶ Fig. 38.1, ▶ Fig. 38.2)

A 53-year-old female presents for screening mammography.

38.2 Key Images

( ▶ Fig. 38.3, ▶ Fig. 38.4)

38.2.1 Breast Tissue Density

The breasts are heterogeneously dense, which may obscure small masses.

38.2.2 Imaging Findings

In the lower inner quadrant of the left breast, there is a subtle area of architectural distortion on the mediolateral oblique (MLO) view. ( ▶ Fig. 38.2). However, it is best seen in the tomosynthesis images ( ▶ Fig. 38.3 and ▶ Fig. 38.4). The right breast was normal (not shown).

38.3 BI-RADS Classification and Action

Category 0: Mammography: Incomplete. Need additional imaging evaluation and/or prior mammograms for comparison.

38.4 Diagnostic Images

( ▶ Fig. 38.5, ▶ Fig. 38.6, ▶ Fig. 38.7, ▶ Fig. 38.8, ▶ Fig. 38.9, ▶ Fig. 38.10, ▶ Fig. 38.11)

38.4.1 Imaging Findings

The diagnostic imaging demonstrates persistent architectural distortion. However, it is best seen on the left mediolateral oblique (LMLO) spot-compression image ( ▶ Fig. 38.6). On this image, longer spicules that draw into a central region can be seen. A focally defined mass is not seen. The ultrasound reveals an irregular mixed hypoechoic mass with angular and indistinct margins located at 7 o’clock 4 cm from the nipple. This 2.1 × 1.3 × 1.3 cm mass has mild posterior acoustic shadowing ( ▶ Fig. 38.8 and ▶ Fig. 38.9). This mass was biopsied with ultrasound guidance. The postbiopsy mammogram demonstrates the biopsy marker clip (ribbon-shaped) in the expected location.

38.5 BI-RADS Classification and Action

Category 5: Highly suggestive of malignancy

38.6 Differential Diagnosis

1. 
   

   Breast cancer (invasive lobular carcinoma): The architectural distortion was best seen on digital breast tomosynthesis (DBT). The additional mammographic images were supportive in the mediolateral oblique (MLO) spot-compression view. The ultrasound confirmed an irregular mass for which biopsy was strongly recommended.

   
   
2. 
   

   Radial scar: Radial scars are known to be elusive on conventional mammographic imaging. The DBT images demonstrate architectural distortion. The diagnostic ultrasound reveals a larger mass than is typical for a radial scar. If an image-guided biopsy yielded a radial scar for this lesion, a surgical consult for excision would be warranted.

   
   
3. 
   

   Normal breast tissue: The DBT images are too worrisome to stop and call this a summation artifact. Findings at DBT without a fully supportive diagnostic mammography evaluation warrant an ultrasound. The ultrasound does not demonstrate normal breast tissue.

38.7 Essential Facts

• 
  

  DBT allows the breast to be viewed in a three-dimensional format allowing for stacks of in-focus planes, or slices, to be viewed thus reducing the impact of superimposed breast tissue.

  
  
• 
  

  Some DBT–only findings can be effaced on conventional diagnostic imaging.

  
  
• 
  

  Architectural distortion and lesion margins are more apparent on DBT.

  
  
• 
  

  Architectural distortion is the most common DBT finding that is mammographically occult.

  
  
• 
  

  Invasive lobular carcinomas have a high frequency of being seen on DBT and of being occult to very subtle on full-field digital mammography (FFDM).

38.8 Management and Digital Breast Tomosynthesis Principles

• 
  

  Architectural distortion on DBT is the most frequently missed sign of breast cancer, and so result in false-negatives on screening mammography.

  
  
• 
  

  The incidence of malignancy for architectural distortion on DBT without a mammographic finding ranges from 21 to 36%.

  
  
• 
  

  Worrisome DBT findings that are not reproduced on conventional mammography warrant evaluation with ultrasound. These cases often are found to be cancers that would otherwise be overlooked mammographically.

  
  
• 
  

  Worrisome DBT findings without an ultrasound correlate warrant either a wire-localization or tomosynthesis-guided biopsy due to the high incidence of malignancy.

38.9 Further Reading

[1] Conant EF. Clinical implementation of digital breast tomosynthesis. Radiol Clin North Am. 2014; 52(3): 499‐518 PubMed

[2] Ray KM, Turner E, Sickles EA, Joe BN. Suspicious Findings at Digital Breast Tomosynthesis Occult to Conventional Digital Mammography: Imaging Features and Pathology Findings. Breast J. 2015; 21(5): 538‐542 PubMed

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