Sedimented calcium in benign breast cysts: the full spectrum of mammographic presentations.

We retrospectively reviewed the mammograms of 318 patients that showed sedimented calcifications within benign breast cysts to describe the natural history and full spectrum of the mammographic appearances. Sedimented calcifications are seen in approximately 4% of symptomatic women undergoing mammography. Their recognition is important to avoid unnecessary workup, follow-up, or biopsy. Key to recognition is the difference in their radiographic features on lateral and craniocaudal views. The classic appearance is that of milk of calcium, seen as linear, curvilinear, or teacup-shaped particles on horizontal-beam lateral views and as ill-defined smudges on vertical-beam craniocaudal views. The most common presentation is multiple, bilateral, scattered and occasionally clustered calcifications within microcysts. Other presentations include milk of calcium within microcysts in a unilateral, clustered distribution; milk of calcium within macrocysts; sandlike calcifications (discrete particles rather than smudges on craniocaudal view) within cysts of various sizes; and rarely, milk of calcium within the lipid cysts of either fat necrosis or galactoceles. None of our cases has proved to be malignant. However, adjacent malignancies are a potential pitfall. We encountered eight patients with carcinoma presenting as clustered microcalcifications in a breast also containing typical sedimented calcifications. In each of these cases, the malignant calcifications could be distinguished by their mammographic appearance. The recognition of sedimented calcifications present in about 4% of symptomatic women undergoing mammography is important because these characteristic calcifications are an indication of benignity. Malignant-appearing microcalcifications found in the vicinity of sedimented calcifications can be distinguished and require biopsy.