If the calcifications are amorphous in shape, they should be biopsied (Category 4). Amorphous calcifications are commonly round, but they are hazy in appearance and do not have sharp, smooth edges. Malignant amorphous calcifications are generally clustered, but occasionally these calcifications may cover a larger area such as a segment or quadrant of the breast. Malignant amorphous calcifications are the result of superimposition of numerous tiny calcifications within the mucin secreted by cells of ductal carcinoma in situ. Sometimes, amorphous calcifications may overlap in appearance with the round, punctate pattern. Very early, tiny amorphous calcifications may appear punctate. If they are initially misidentified, this error would be discovered as long as the calcifications are closely followed.
Heterogeneous or pleomorphic calcifications are irregular in shape. Furthermore, they also vary in size and density (Fig. 1–4). These calcifications have also been described as resembling “crushed stones” or “granulated sugar.” The larger calcifications are commonly larger than amorphous calcifications, but they are still smaller than 0,5 mm in size. Malignant heterogeneous calcifications generally present in a cluster unless the patient presents with advanced disease. These calcifications are commonly the result of necrosis from intermediateor lower-grade ductal carcinoma in situ. Therefore, heterogeneous calcifications should be biopsied (Category 4).
Like heterogeneous calcifications, fine linear and branching calcifications are irregular calcifications that vary in size and density. However, unlike heterogeneous calcifications, these calcifications form thin, irregular lines that occasionally branch. These calcifications are generally clustered, but extensive disease will present with a segmental distribution. These calcifications should be biopsied (Category 4). High-grade ductal carcinoma in situ produces extensive calcified necrosis that fills the ducts. The configuration and alignment of these calcifications mirror the intraductal spread of malignancy. When a large number of these calcifications are present, they are extremely suspicious, and in those cases, assessment of these calcifications may be upgraded to Category 5.
Architectural Distortion
Generally, mammographers easily recognize asymmetric densities or calcifications unless these findings are small or partially obscured by normal fibroglandular tissue. However, perception of architectural distortion is more difficult since parenchymal patterns vary with different individuals. Perception and characterization of architectural distortion are aided by recognizing normal parenchymal anatomy. The breast parenchymal pattern consists of thin, curvilinear lines that are directed toward the nipple. This radiating pattern is only broken by blood vessels. Adjacent to the subcutaneous fat, the Cooper's ligaments form a scalloped parenchymal edge. The parenchymal edge generally thins out into the axilla and chest wall. These areas commonly form ill-defined curvilinear, feathery borders in patients with scattered or heterogeneously dense breasts. In patients with extremely dense breasts, these borders tend to be well defined. However, the contours are still curvilinear. With heterogeneously dense and extremely dense breasts, the superior corner of the MLO view and the medial and lateral corners of the CC view are also generally curvilinear or rounded.
Figure 1–4. (A). Right MLO digital mammogram. (B). Right CC digital mammogram. (C). Right MLO digital mammogram (close-up). (A–C). In the upper outer quadrant of the right breast, there is a palpable lump that is labeled with a radiopaque dot. Just distal to the dot are extensive heterogeneous calcifications. (D). Right antiradial breast sonogram: The palpable mass corresponds to a combination of a cyst and a spiculated hypoechoic mass with punctate calcifications. Mastectomy specimen shows that this sonographic mass and the mammographic calcifications are mixed infiltrating lobular and ductal carcinoma with an extensive intraductal component.
Architectural distortion may either be central or peripheral (see Section 7). Central distortion results when the ductal and trabecular lines deviate from the nipple. This distortion is commonly due to a spiculated lesion producing straight lines that point to the center of the abnormality. Commonly, these abnormal spiculations are thicker than normal trabecular lines (Fig. 1–5).
Abnormalities that affect the edge of the parenchyma cause peripheral architectural distortion. Lesions may cause retraction, flattening, straightening, or bulging of the parenchymal contours (Fig. 1–6). When the density in the superior parenchymal edge of the MLO view is affected, it may form a sharp triangular corner. Although some women normally have sharply angulated parenchymal corners, if there is asymmetry between the corners or if there has been a change in configuration, then one should search for a subtle spiculated lesion (Fig. 1–7). Retraction of the posterior edge of the parenchyma has been labeled the “tent sign” as the retraction produces a biconvex V-shaped border resembling the peak of a tent (Fig. 1–8).
When architectural distortion is present, the breast imager should perform additional mammographic views to identify a mass. Spot compression views may demonstrate a spiculated mass. Oblique views may clarify the location of architectural distortion that is initially visible only on one view. Magnification views may be useful to identify associated malignant calcifications.
Figure 1–5. (A). Right MLO mammogram. (B). Left MLO mammogram. (C). Right CC mammogram. (D). Left CC mammogram. (E). Left CC spot compression mammogram. (A–E). Central architectural distortion: In the lefi CC view (D) there is an area of focal architectural distortion (square). The lesion corresponds to the asymmetric density in the superior breast on the MLO view. This architectural distortion is due to a tumor consisting of lobular and infiltrating ductal carcinoma.
Figure 1–6. (A). Right MLO mammogram. (B). Left MLO mammogram. (C). Right CC mammogram. (D). Left CC mammogram. (A–D). Peripheral architectural distortion: A lobulated mass extends outside the posterior border of the fibroglandular border (square). This mass corresponds to an infiltrating ductal tumor.
Figure 1–7. (A). Right MLO mammogram. (B). Left MLO mammogram. (C). Right CC mammogram. (D). Left CC mammogram. (E). Right MLO spot magnification mammogram. (F). Right CC spot magnification mammogram. (A–F). Superior peripheral architectural distortion: An irregular mass (marked by a square) at 12:00 produces a sharp angulation of the superior parenchymal corner in the right MLO view (A). This mass represents tubular carcinoma.
Figure 1–8. (A). Right MLO mammogram. (B). Left MLO mammogram. (C). Right CC mammogram. (D). Left CC mammogram. (E). Left MLO spot magnification mammogram. (F). Left CC spot magnification mammogram. (A–F). Posterior peripheral architectural distortion (tent sign): In the left CC view (D), the posterior parenchymal border exhibits retraction (marked with a V). Spot magnification view demonstrates that the architectural distortion is associated with amorphous calcifications (F). Although the abnormality is difficult to identify in the left MLO view (B), left spot magnification locates the lesion with microcalcifications in the superior breast (E). The mass is an infiltrating ductal carcinoma.
Causes of architectural distortion include focal fibrosis, sclerosing adenosis, fat necrosis, scar, radial scar, and malignancy. One identifies surgical scars and fat necrosis by correlating regions of previous surgery or trauma with the architectural distortion. Radial scars usually have thin spiculations and a radiolucent center. Neoplasms usually produce architectural distortion that is evident on two orthogonal views and is associated with