Milk of calcium within tiny benign breast cysts.

Small amounts of milk of calcium settling to the bottom of multiple tiny benign breast cysts produce the mammographic picture of clustered linear and curvilinear calcifications when imaged in lateral projection with a horizontal x-ray beam. These calcifications, although benign, may be confused with the microcalcifications of carcinoma. Milk of calcium is found much more frequently in small breast cysts than anywhere else in the body. It is not at all uncommon, occurring in more than 4% of women undergoing diagnostic mammography. Fortunately, the overall mammographic appearance of milk of calcium cysts is quite characteristic, permitting them to be a differentiated from malignant breast microcalcifications with a high level of confidence.