Breast architectural distortion

Breast architectural distortion is a descriptive term in breast imaging (mammography, ultrasound, and MRI) to indicate that the breast parenchyma is tethered or indented. The finding per se is not a mass.

Pathology

Architectural distortion is often due to a desmoplastic reaction in which there is focal disruption of the normal breast tissue pattern. There are several features that can be considered as part of architectural distortion ³:

• contour abnormality
• trabecular thickening
• trabecular disorganization

Etiology

Many entities can cause architectural distortion ^1,4. In practice, the most common are surgery and malignancy. It is considered the third most common appearance of breast cancer ^1,6.

• primary causes
  • invasive breast cancer, including both invasive lobular carcinoma and invasive ductal carcinoma
  • ductal carcinoma in situ
  • radial scar/complex sclerosing lesion
  • fat necrosis
  • sclerosing adenosis
  • fibromatosis
• secondary causes 
  • postsurgical scars (most common)
  • trauma
  • infection

Radiographic features

Architectural distortion can be visually subtle. Compared to 2D mammography, digital breast tomosynthesis increases the sensitivity, confidence, and interobserver agreement in detection of architectural distortion ^7-10. Tomosynthesis also helps localize the abnormality. Targeted ultrasound should then be performed to confirm the finding, but MRI is an alternative if no ultrasound correlate is found ⁹.

Mammography/US/MRI

Architectural distortion is characterized by a number of possible appearances ⁵:

• radiating thin straight lines or spiculations
• focal retraction, distortion, or straightening at the edge of the parenchyma
• blurring of normal tissue planes such as the fat-fibroglandular junction
• straightening or thickening of Cooper ligaments
• compression of tissue around a mass

Radiology report

Architectural distortion can be reported as a standalone finding or be associated with (adjacent to) another finding, such as asymmetry, calcifications, or mass. In most cases, architectural distortion is a suspicious finding (BI-RADS 4) ^8,9. The BI-RADS Atlas suggests that an ultrasound finding of architectural distortion thought to be due to postsurgical scar may be categorized as probably benign (BI-RADS 3), but there is sparse data supporting this approach ⁵.

See also

• other imaging features of breast malignancy
  • masses
  • asymmetries
  • calcifications