benign microcalcificationsAggregates of precipitated calcium salts, which by light microscopy appear as purplish crystalline debris. Benign microcalcifications usually lack clinical significance and occur in various tissues—e.g., blood vessel walls in atherosclerosis—or in necrosis.
Type I—Occur in benign lesions of the breast (e.g., 1Sclerosing adenoma, fibrocystic disease, proliferative fibrocystic disease, fibroadenoma, atrophy, fibrosis); type I MCs are birefringent, colourless, composed of calcium oxalate and poorly visualised without polarisation.
Type II—Occur in benign and malignant lesions of the breast (e.g., ductal carcinoma, lobular carcinoma, ductal CIS, lobular CIS, atypical ductal hyperplasia, atypical lobular hyperplasia); type II MCs are a deep purplish colour by light microscopy, and composed of calcium phosphate.
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