Calcifications

Calcifications are commonly encountered in breast imaging and frequently present a diagnostic dilemma. While sometimes calcifications have a typical appearance and can be easily classified as benign or malignant, many remain indeterminate. Furthermore, calcifications due to benign and malignant processes can coexist in close proximity within the breast, and therefore it is important to carefully evaluate all calcifications. When new calcifications that cannot be readily classified as typically benign are seen on screening mammography, the patient should be recalled for additional evaluation with magnification views in the CC and true lateral projections. Magnification views allow the breast imager to better visualize the morphology and distribution of calcifications, as well as reveal finer calcifications that may not be visible on the conventional screening views. The orthogonal views (CC and true lateral) are important as these allow the breast imager to determine the distribution of calcifications as grouped, segmental, regional, or diffuse, as well as help with biopsy planning if needed. The biopsy of calcifications, in the absence of an associated ultrasound-detected mass, is performed with mammographic guidance, and the specimen is radiographed at the time of the biopsy to ensure that an adequate amount of calcifications are present within the samples. A biopsy marking clip is usually deployed within the biopsy site, and a post-biopsy mammogram is obtained to ensure that the clip is present within the area of the targeted calcifications. This is particularly important in cases where several groups of calcifications are present in the same region within the breast; the post-biopsy mammogram serves as a “final check” to ensure that the correct group of calcifications was sampled. On histology, two types of calcifications are identified: (1) Phosphate-type and (2) Oxalate-type. Phosphate-type calcifications are the common type of breast calcifications which can be present in association with a spectrum of benign and malignant neoplastic epithelial proliferations. Phosphate-type calcifications are acellular, amorphous, and dark blue and purple colored in the H&E-stained sections. The second Oxalate-type calcifications are pale-yellow and translucent in appearance on the H&E sections. Oxalate-type calcifications are limited to apocrine cysts and dilated ducts and are frequently found in a clinical setting of “milk of calcium”. It is a routine pathology practice to identify the association of calcifications in the breast histological sections, especially in the core needle biopsies, when the sampling is performed for calcifications. A search for calcifications in the histological sections is often straightforward. The tissue in the stereotactic core biopsies is thick, therefore, sometimes the calcifications are identified on additional tissue levels and deeper tissue sections. Multiple tissue levels, sometime exhausting the tissue in the block and X-ray of the tissue block may be needed to ensure that the target calcifications were sampled and identified in the histological sections. A rad-path correlation is always warranted if the calcifications are not identified in the histological sections of the breast tissue removed for calcifications. Rarely the calcifications in the breast tissue are related to dystrophic or metaplastic ossification.