Light micrograph of a breast microcyst (the circular blue structure) containing calcium oxalate crystals (the clear-yellowish irregular shaped structures within the light blue area). Calcifications such as these are often detected on mammography by a radiologist. The presence of the crystals is then confirmed by pathologists examining breast biopsy tissue to rule out breast cancer. Haematoxylin and eosin stained tissue section. Magnification: 200x when printed at 10 cm.