Calcifications found with a mass provide further information about that particular mass. For example, an involuting fibroadenoma will often contain popcorn-like macrocalcifications. Similarly, fine curvilinear calcifications at the margin (i.e. rim calcifications) of a round or oval mass indicate a benign process. On the other hand, a mass with pleomorphic, irregularly shaped calicifications heterogeneous in size and morphology raises much greater concern about malignancy.

Calcifications are analyzed according to their size, shape, number, and distribution. The general rule is that larger, round or oval shaped calcifications uniform in size has a higher probability of being associated with a benign process and smaller, irregular, polymorphic, branching calcifications heterogeneous in size and morphology are more often associated with a malignant process. Certain calcification patterns are almost always pathognomic of a benign process, and in such cases no further analysis is needed. In the majority of cases, however, a pattern of calcification deposition is inconclusive and may be attributable to either a benign or malignant process. Needless to say, these cases require additional evaluation such as using magnification mammography to further elucidate the calcifications' morphology and distribution.

Size
Generally speaking, microcalcifications are associated with a malignant process and macrocalcifications are associated with a benign process. The problem with this general rule is that there is no fine line of measurement that could enable one to distinguish between micro and macro. All calcifications start out imperceptably small and radiographically invisible. Most radiologists place calcifications 0.5 mm or less to have a high probability of association with cancer; and calcifications of 2.0 mm or larger are typical of a benign process. The smallest visible calcifications on a mammogram is approximately 0.2 - 0.3 mm.

Number
The number of calcifications that make up a cluster has been used as an indicator of benign and malignancy. While the actual number itself is arbitrary, radiologists tend to agree that the minimum number of calcifications be either four, five, or six to be of significance. Any number of calcifications less than four will rarely lead to the detection of breast cancer in and of itself. Again, as with all criteria in mammographic analysis, no number is absolute and two or three calcifications may merit greater suspicion if they exhibit worrisome morphologies.

Morphology
The morphology of calcifications is considered to be the most important indicator in differentiating benign from malignant. As noted earlier, round and oval shaped calcifications that are also uniform in shape and size are more likely to be on the benign end of the spectrum. Calcifications that are irregular in shape and size fall closer to the malignant end of the spectrum. It has been described that calcifications associated with a malignant process resemble small fragments of broken glass and are rarely round or smooth.

ACR BIRADS Classification
The American College of Radiology (ACR) Breast Imaging Reporting and Data System (BIRADS) has classified findings of calcifications into three categories: (1) Typically benign; (2) Intermediate concern; and (3) Higher probability of malignancy. The pages that follows will describe the type of calcifications that fall into these categories.