Breast calcifications

Breast calcifications are deposits of calcium salts in the breast, which are radio-opaque on mammography. The majority are benign, but they can arisebe associated with cancer. The ability to diagnose and appropriately manage the significant microcalcifications and differentiate them from a vast numberinnocuous findings is part of aetiologiesthe art and science of breast imaging.

Epidemiology

TheyCalcifications are extremely common and can be, present in ~85% of mammograms ⁸. Their frequency increases with age. Up

In a screening mammography program, the rate of recall because of calcifications was 1.7% and of these, 19% resulted in a cancer diagnosis ¹³. In the digital mammography era, about one-sixth of all recalls are for calcifications ¹⁵.

Calcification-specific cancer detection rates in the era of digital mammography range from 1.9 to 3.2 in 1000 screened ^13,14. A third of breast cancers show calcifications as the only mammographically suspicious feature ¹³. Up to 50% of breast cancers can be associated with calcification while 15-30% of calcifications biopsied for various reasons tend to be malignant in asymptomatic patients ¹⁰.

Pathology

Calcification can compriseOf the breast cancers detected on mammography due to calcifications, about two-thirds represent ductal carcinoma in situ and the remainder are invasive ductal carcinoma^13,14. In contrast, the causes of: benign calcifications are broad and covered in detail in other sections (Radiographic features and Differential diagnosis).

• Microscopic appearance

  Calcifications typically represent calcium phosphate salt deposition: stains purple on routine H&E stain

• or calcium oxalate salt deposition: can be difficult to visualise. The former appear purple on H&Ehematoxylin and eosin stain, while the latter requires the use of polarized light to assess birefringence

Classification

Radiographic features

Breast microcalcifications can be grouped according to location,The BI-RADS lexicon prescribes descriptors for typically benign calcifications as well as suspicious morphologic terms and descriptors of calcification distribution, morphology or underlying aetiology. See also the separate article on breast calcifications: an approach.

• skin: well-defined, usually punctate and if multiple, spread throughout the breast; most of themthey have a smallvery fine lucent centre; and tend to lookthey are seen in the same with no pleomorphism; these may be bilateral
• intraductal calcification withinskin line on the edge of the breast tissue: theseand are either the calcifications of DCIS or castingvery small punctate calcifications in a duct
• milk of calcium within a breast cyst: the classic "tea cups" that show a level on the mediolateral view but a smudge on the CC viewskin pores
• vascular calcification in breast tissue: when when extensive they are easy to pick up; when they are just isolated in one vessel they can potentially be confused with DCIS; the vessel has two walls and in most cases a tram line can be visualised if both walls are calcified
• coarse or "popcorn-like": they haveinvoluting fibroadenoma
• large rod-like
• round: circular in morphology, small (<1 mm) or punctate (<0.5 mm) in size; frequently formed in acini of terminal ductal lobular unit
• rim
• dystrophic
• milk of calcium: the classic "tea cups" that show a very fine lucent centre; they are seen in the skin linelevel on the edge ofmediolateral view but a smudge on the breast and are very small punctate calcifications in the skin poresCC view
• suture calcification within breast tissue

Suspicious morphology of calcifications

• amorphous
• stromal calcification withincoarse heterogeneous
• fine pleomorphic
• fine linear or fine-linear branching

See also the separate article on suspicious breast tissuecalcifications

Distribution

• diffuse/scattered calcification: may may be scattered calcifications or multiple similar appearing clusters of calcifications throughout the breast
• regional calcification: scattered scattered in a larger volume (>2 cc) of breast tissue and not in the expected ductal distribution
• grouped calcification: at at least 5 calcifications within 1 cm from each other, in an area at most 2 cm in greatest dimension
• linear calcification: calcifications calcifications arrayed in a line suggestive of deposition along ducts
• segmental calcification: calcium calcium deposits in ducts and branches of a segment or lobe

Morphology

• microcalcifications within breast
  • pleomorphic microcalcifications within breast: different shapes, sizes and densities

    Radiology report

    Calcifications that are potentially alarming;definitely benign do not need to be reported, so that the referrer or patient reading the report would not be confused reading the report, but they may be reported if there is concern that other observers might not interpret them as benign ¹⁷.

    Round calcifications are benign (BI-RADS 2) if diffuse or stable for several years. Grouped round calcifications in isolation are probably benign (BI-RADS 3). Round calcifications that are new, increase, or linear or segmental in distribution are suspicious (BI-RADS 4).

    Differential diagnosis

    There are many etiologies of breast calcifications.

    Ductal calcifications may represent either the calcifications of DCIS are different shapes, sizes and densities. They are wild and crazy and have been described as "X's Y's and Z's" whichor casting calcifications in many cases is quite true

  • rounded microcalcification within breast
  • punctate microcalcification within breast
  • amorphous calcification within breast
• macrocalcifications within breasta duct
  • coarse macrocalcifications within breast
  • popcorn calcification within breast - involution of a fibroadenoma
  • egg shell/rim calcification within breast

Underlying aetiology

• from fat necrosis
• from malignancy
  • intraductal calcification
  • psammomatous calcification from mucin producing tumours
• fromfibrocystic change
  • liponecrosis microcystica
  • from an oil cyst
• from secretary calcification: plasma cell mastitis
• from a degenerating fibroadenoma
• from an underlying metabolic abnormality
  • tumoral calcification within breast
  • dystrophic calcification within the breast
• from parasitic infestations
  • loaisis of the breast
  • trichinosis of the breast

Note on segmental distribution

If microcalcifications are distributed in a segment of the breast they deserve special attention. Calcifications running from the nipple posteriorly in a breast segment is a potentially sinister sign and the possibility of DCIS involving a whole breast segment should be kept in mind. See case 18966.

Why breast calcifications are significant

There are two main reasons why calcifications are potentially significant:

1. A percentage of breast malignancies present as microcalcifications before they present as a mass. The prime example is DCIS, a non-obligate precursor of infiltrating ductal carcinoma. In the days before senology was accepted as a diagnostic technique, the diagnosis of breast cancer was made after the patient presented with a mass or metastases or post mortem. Depending on which reference you use, the incidence of DCIS in large screening series is around 30%. Coincidentally, this is also the rate of decreased mortality attributed to screening in the literature.

2. The second reason breast calcifications are important is the science involved to be able to diagnose and manage and distinguish significant microcalcifications from insignificant ones. The ability to diagnose and appropriately manage the significant microcalcifications and differentiate them from innocuous findings is part of the art of breast imaging.

The ability to diagnose a malignancy early implies that the disease is potentially curable with less chance of metastatic disease and with potentially less invasive surgery. Coupled with improvements in therapy, this shows why regular screening mammography results in more people surviving.

A suggested initial approach

For the novice, the interpretation and approach to breast calcifications can be intimidating. An approach is to use reference 12 below. The book is readable in a weekend and gives a morphological atlas as well as differential diagnosis to the most commonly encountered calcifications in the breast. The illustrations are good and representative and serve as a good guide. The breast section of this site contains a wide variety of cases to review.

See also

• breast calcifications: an approach
• suspicious breast calcifications