The American College of Radiology (ACR) BI-RADS provides ter- minology to describe benign and suspicious calcification mor- phology and distributions on mammography (Box 3.1) as well as associated findings (Box 3.2). The BI-RADS report of calcifications includes size of calcific group, location, morphology/distribution, associated findings, change from previous studies, BI-RADS Final Assessment category, and management recommendations (Box 3.3). The BI-RADS helps radiologists classify calcifications into benign or malignant entities, prompting patient management, and provides powerful descriptors that help clinicians understand the seriousness of a finding. For example, the suspicious BI-RADS cal- cification term fine pleomorphic prompts the radiologist to clas- sify the calcifications into BI-RADS Final Assessment category 4 Suspicious and prompts biopsy. The BI-RADS term large rodlike indicates benign ductal ectasia and prompts classification to Comedo Micropapillary Cribriform Solid
FIG. 3.5 Schematic of architectural pattern of ductal carcinoma in situ (DCIS) in cross section. Note the spaces (white) in the DCIS tu- mors, in which the calcifications form. These calcifications may be amorphous, coarse heterogeneous, fine pleomorphic, fine-linear, or fine linear–branching shapes.
Morphology: Fine linear or fine-linear branching Distribution: Linear or segmental
Morphology: Amorphous, fine pleomorphic, etc Distribution: Linear or segmental
A
C D
B
FIG. 3.6 Classical morphology and distribution of calcifications in ductal carcinoma in situ (DCIS). (A and B) Intraductal spread can result in fine-linear or fine linear–branching individual calcification morphologies when the DCIS calcified necrotic center extends along the duct. This morphology of calcifications is typical for comedo- type DCIS. Schematic (A) and representative case (B). (C and D) However, DCIS does not always produce fine- linear or fine linear–branching calcifications. For example, when calcifications form in lumens or small pockets of DCIS, the morphology of individual calcification particles may be amorphous or fine pleomorphic. If the duct is packed with tiny calcifications, the mammography can show linear (including linear branches) or segmental calcification distributions. This distribution pattern is also suggestive of DCIS components.
C
E
G H
F D
FIG. 3.7 Variety of calcifications in ductal carcinoma in situ (DCIS). Pathologic–radiologic correlation. (A and B) High-grade DCIS with comedo necrosis. Large central calcifications (A; arrows) developing in comedo necrosis results in fine-linear and fine linear–branching calcifications on mammography highly suggestive of DCIS (B). (C and D) Intermediate-grade DCIS showing cribriform architecture. Microcalcifications (C; arrows) within ducts produces fine pleomorphic calcifications in linear distributions on mammography (D). The linear distribution is typical for DCIS. (E and F) Low-grade DCIS with cribriform and papillary architecture. Microcalcifications in small pockets and central lumens of cribriform DCIS (E; arrows) are shown as amorphous calcifications (F; ar- rows) on mammography. This case has no unique findings for DCIS, and it is difficult to differentiate amorphous calcifications in DCIS from amorphous calcifications in benign disease. (G and H) Intermediate-grade DCIS with cribriform architecture. Multiple small microcalcifications (G; arrows) are likely caused by the secretions within ducts. On mammography, there is only one calcification seen (H; arrow). Note that not all calcifications seen on pathology can be seen on the mammogram. (Courtesy Shotaro Kanao, M.D., Ph.D. and Tatsuki R. Kataoka, M.D., Ph.D., Kyoto University, Kyoto, Japan.)
Acinus ductule
TDLU
Duct
Calcifications associated with DCIS
Large rod-like calcifications
Round calcifications Milk of calcium Acinus
Periductal
Dilated duct Intraductal
Dilated acini or lobules
Fine linear and fine-linear branching
Amorphous, fine pleomorphic, etc.
FIG. 3.8 Calcification location correlated to BI-RADS terminology. Round benign calcifications and milk of calcium form in acini or ductules. The ductal carcinoma in situ (DCIS) starts in the terminal ductal and lobular unit (TDLU) epithelium and can extend into ducts. Benign large rodlike calcifications from secretory disease or duct ectasia also forms in or around ducts but are larger, sharper, and coarser than DCIS calcifications. To distinguish benign-appearing from malignant-appearing calcifications, analyze both the individual calcification morphology and their distribution.
MLO
A
FIG. 3.9 Systemic search to find calcifications on digital mammography. (A) First, do a systemic search in stripes over the entire breast.
B
C
D E
FIG. 3.9 cont’d (B) Second, on electronically magnified views, systematically search the upper half of the mag- nified breast. (C) Third, systematically search for the lower half of the magnified breast. (D) Then, you can find the calcifications associated with a mass (circle). (E) A photographically magnified view of D shows bright white calcifications (arrows) within the mass shadow. Biopsy showed invasive ductal cancer. Note that a BB marker is placed at the palpable portion on the skin.
BI-RADS Final Assessment category 2 Benign, return to screen- ing. This chapter will illustrate and classify breast calcifications in benign or malignant categories using BI-RADS terminology.
Typically Benign Calcifications
Recognizing typically benign calcifications as “don’t touch”
lesions allows the radiologist to leave them alone (Box 3.4).
Generally, benign calcifications are dense and have a unique morphology or location. Classic benign calcifications require no further workup and should prompt no further action. However, some benign calcifications mimic malignant calcifications (Box 3.5), and tiny, subtle calcifications may be difficult to classify as benign or malignant in particular. However, recognizing clues for classification into appropriate BI-RADS lexicon terms may help the radiologist make the correct diagnosis. Box 3.6 shows
Tomo slice
H
Tomo-synthesized 2D Tomo-synthesized 2D
Tomo-synthesized 2D
Tomo slice
Scroll
Spot mag
Tomo slice
Tomo slice Scroll
Scroll
Tomo-synthesized 2D
A
B
C D
E
F
G
I
FIG. 3.10 Systemic search to find calcifications on tomosynthesis. (A–D) Tomosynthesis synthesized 2D mammograms of right craniocaudal (CC) views. To detect and analyze calcifications using tomosynthesis, start by reviewing the synthesized 2D mammograms (or conventional 2D). Do a systemic search in a zigzag pattern or in stripes over the entire breast (A), the upper half (B), and the lower half (C) of the magnified breast, using the same process described in Fig. 3.9. The photographic magnification view (D) shows grouped microcalcifications (circle) in the middle right breast. (E–H) Key slices of tomosynthesis right CC projection views at the level of calcifications. Try to find microcalcifications in a movie showing all tomosynthesis slices in Video 3.1A (standard view) and B (electronically magnified). First, review the entire breast in slices with scrolling slices (E). Place your attention on the upper half (F) and the lower half (G) of the breast with scrolling slices. Finally, pay attention to the retroareolar and axillary regions with scrolling slices. Then scroll through any suspicious areas with electronic magnification and correlate to the area on the orthogonal view, just like you would with a 2D mammogram. Then direct your attention to the location of the detected calcifications on the appropriate tomosynthesis slices and carefully analyze the calcifications (circle) with electronic magnifica- tion to determine whether they need further analysis (H; Video 3.1B). Try to find microcalcifications in a movie showing all tomosynthesis slices in Video 3.1A (standard view) and B (electronically magnified view). In this case you would detect and recall grouped microcalcifica- tions initially spotted on the synthesized 2D mammogram. Note a benign round calcification with a linear shadow artifact (arrowhead). (I) Spot magnification CC view of the conventional 2D mammogram shows grouped fine pleomorphic calcifications.
A B
FIG. 3.11 Air-gap spot magnification view using a 0.1-mm focal spot: a technique to visualize calcifications bet- ter. (A) Photographically magnified view of conventional 2D craniocaudal (CC) view of calcifications taken with a 0.3-mm focal spot. (B) Photographically magnified view of air-gap spot magnification mammogram of the cal- cifications with a 0.1-mm focal spot showing the calcifications sharper than the conventional mammogram (A).
BOX 3.1 Breast Imaging Reporting and Data System Terms for Calcifications
TYPICALLY BENIGN Skin
Vascular
Coarse or “popcorn-like”
Large rodlike Round Rim Dystrophic Milk of calcium Suture
SUSPICIOUS MORPHOLOGY Amorphous
Coarse heterogeneous Fine pleomorphic
Fine linear or fine-linear branching DISTRIBUTION
Diffuse Regional Grouped Linear Segmental
From ACR BI-RADS Mammography, In ACR BI-RADS atlas, breast imaging report- ing and data system, Reston, VA, 2013, American College of Radiology.
BOX 3.2 Associated Findings with Calcifications Mass
Architectural distortion Axillary adenopathy Skin retraction Nipple retraction Skin thickening
Trabecular thickening (breast edema)
From ACR BI-RADS Mammography, In ACR BI-RADS atlas, breast imaging report- ing and data system, Reston, VA, 2013, American College of Radiology.
BOX 3.4 Typically Benign Calcifications (American College of Radiology Breast Imaging Reporting and Data System Terminology): Don’t Touch Calcifications Skin calcifications
Vascular calcifications (tram-track appearance) Coarse or “popcorn-like”
Fibroadenoma (mass with round, coarse peripheral calcifications) Large rodlike
Plasma cell mastitis or secretory disease (needle-like or sausage- shaped calcifications pointing toward the nipple; found in middle-aged women; benign entity, usually asymptomatic) Round calcifications
Rim calcifications (with radiolucent centers) Calcifying oil cysts
Intraparenchymal calcifications
Skin calcifications (obtain tangential views) Fat necrosis (postbiopsy, posttrauma)
Dystrophic calcifications (be alert for such calcifications in women after biopsy for cancer)
Milk of calcium (linear on the mediolateral view, smudgy on the craniocaudal view)
Suture calcifications (cat gut, postradiation)
BOX 3.5 Benign Calcifications that Simulate Ductal Carcinoma in Situ
SKIN CALCIFICATIONS
Scattered calcifications projecting as a group in one projection Sclerosing adenosis
Fibrocystic change
BOX 3.3 Calcification Report Size of the calcific group
Location (right or left breast, quadrant or clock position, centime- ters from the nipple)
Calcification descriptors, including characteristics of the worst- looking individual calcifications in the group
Distribution of the calcifications Associated findings
Change, if previous films are compared BI-RADS code
Management recommendation
BI-RADS, Breast Imaging Reporting and Data System.
From ACR BI-RADS Mammography, In ACR BI-RADS atlas, breast imaging report- ing and data system, Reston, VA, 2013, American College of Radiology.
characteristics of benign calcifications according to individual morphologies and distributions that distinguish them from malig- nancy. Artifacts mimicking calcifications are not included in the BI-RADS lexicon, but these fake “calcifications” will also be illus- trated in this chapter (Box 3.7).