According to the American Cancer Society, calcifications or microcalcifications seen on a mammogram are small mineral deposits that show up as white spots on the mammogram film. Calcifications can be benign, but may be a sign of breast cancer.

Calcifications may be sorted into two groups, macrocalcifications and microcalcifications.

Macrocalcifications are larger deposits of the mineral calcium, and are most likely caused by aging of the breast arteries, old injuries, or inflammation. These deposits are related to non-cancerous conditions and do not require a biopsy.

Microcalcifications are small pieces of calcium in the breast tissue. They may appear alone or in clusters. Microcalcifications are more worrisome, but do not always signal the presence of cancer. The shape and pattern of microcalcifications will help determine whether a cancer is present. In most cases, microcalcifications do not require a biopsy.

Sometimes calcifications are monitored by additional tests, including repeat mammograms. In other cases, the microcalcifications are more suggestive of cancer and a breast biopsy will be recommended. This will be done especially if the calcifications are tightly clustered, or show characteristics that are worrisome to the radiologist.