Microcalcifications are tiny deposits of calcium in the breast issue, according to WebMD. The deposits show up on mammograms as tiny white dots. While generally not caused by cancer, microcalcifications can indicate early breast cancer or the presence of precancerous cells in the breast.
Microcalcifications don't typically cause symptoms and are too small to feel during a breast exam. Microcalcifications that are clustered together in a particular pattern are sometimes indicative of cancer, states WebMD. A woman with microcalcifications may undergo a second, more detailed, mammogram to determine if the spots are an early sign of cancer. If the second mammogram determines the microcalcifications could be due to cancer, the patient may have a biopsy to further examine the tissue.