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Atlas of breast cancer early detection

Breast imaging – Mammography technique – Pitfalls in techniques of mammography – Incorrect MLO positioning


Technical factors may be responsible for an abnormal finding on mammography and may lead to misinterpretation. Some of the technical factors that cause false-positive and false-negative findings on mammography interpretations are described in the following sections.

The nipple mimicking a lesion in the central quadrant

Probable cause – incorrect MLO positioning
If the breast support is too low, it can cause the breast to roll in and the nipple to turn in when compression is applied. This turned-in nipple may cause a shadow, which can be mistaken as a mass in the retroareolar region.

  • Ensure that the breast is positioned correctly, with the nipple in profile, and that the breast support and lower compression paddle are at the appropriate heights. The image thus obtained will reveal a correctly placed nipple shadow in profile.
  • A true retroareolar mass, if present, will be projected separate from the nipple shadow.
  • Targeted breast ultrasound in the region of concern will confirm the presence of the mass, if any.


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