Sclerosing adenosis of the breast

Sclerosing adenosis (SA) is a benign proliferative condition of the terminal duct lobular units characterised by an increased number of acini and their glands. It manifests as multiple small, firm, tender nodules, fibrous tissue, and variable microcysts within the breast. It is sometimes placed under the category of borderline breast disease.

Clinical presentation

Many women with sclerosing adenosis experience recurring pain that tends to be linked to the menstrual cycle.

In most cases, sclerosing adenosis is detected during routine mammograms or following breast surgery. A biopsy is required to confirm the diagnosis, because the condition may be difficult to distinguish from breast cancer by imaging.

Sclerosing adenosis can appear as a focal or diffuse lesion. It is not physically palpable in 80% of the cases, although in some cases may cause skin retraction.

Sclerosing adenosis is a type of adenosis in which enlarged acini become slightly distorted by surrounded stromal fibrosis ("sclerosis"). The normal lobular architecture of the breast is maintained, but becomes exaggerated and distorted.

Sclerosing adenosis can be seen as a component of other proliferative lesions, such as:

Sclerosing adenosis has a wide range of mammographic presentations, and can be difficult to distinguish from an infiltrating carcinoma:

  • mass, with irregular to well-defined contours
  • architectural distortion
  • microcalcifications
    • present in 40-55% of cases 5,6
    • may be amorphous, pleomorphic, or punctate 3,5
    • more commonly clustered, although may present in diffuse scattered distribution 3,5

Although not considered a pre-malignant lesion, sclerosing adenosis is considered an independent risk factor for development of subsequent breast cancer 3,5. Studies suggests that women with sclerosing adenosis may have approximately 1.5-2 times as high a risk of developing breast cancer

Breast imaging and pathology
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Article information

rID: 12787
System: Breast
Tag: cases
Synonyms or Alternate Spellings:
  • Sclerosing adenosis
  • Sclerosing adenosis of breast
  • Mammary sclerosing adenosis

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    Case 1: mammogram
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