Short Posterior Nipple Line With Subpectoral Implants
A 5-foot, 100-pound 54-year-old woman is referred for diagnostic evaluation of a new palpable lump in the left upper outer quadrant. She has bilateral subpectoral breast implants placed 12 years ago. On the technologist's first attempt at a standard CC view, the implant is not displaced posteriorly, the posterior nipple line is short, and much of the posterior breast is obscured by the implant. The patient reports no pain but says the compression "felt like it was on the implant." She has no prior implant imaging at your facility, and the radiologist has ordered "bilateral diagnostic mammography."
1. What views should be obtained and why?
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Both implant-displaced and implant-included views, bilaterally.
Implant-displaced (Eklund) CC and MLO:
- The implant is pushed posteriorly against the chest wall while the native breast tissue is pulled forward over it and compressed.
- This is the only way to evaluate the fibroglandular tissue; an implant-included view on a small breast is largely a picture of the implant.
- The new palpable lump in the upper outer quadrant will only be characterized on displaced views, plus a marker and, if needed, spot compression/tangential views.
Implant-included CC and MLO:
- Needed to evaluate the implant itself: shell integrity, contour, capsule, and any peri-implant collection.
- Subpectoral placement and 12 years of age make silent rupture a real consideration, and that diagnosis is made on implant-included views and ultrasound.
Skipping either set leaves half the clinical question unanswered.
2. How do you know whether the implant-displaced views are adequate, and what criteria do you apply at the workstation?
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Adequacy criteria for the displaced view:
- The posterior nipple line on the displaced view should be within about 1 cm of the posterior nipple line on the corresponding implant-included view. If it is much shorter, tissue is being lost behind the implant.
- The implant should be visible as a separate structure posteriorly, not superimposed on the compressed breast.
- On the MLO, the inframammary fold must be included and the pectoralis muscle should reach the posterior nipple line.
- The nipple must be in profile and the marker on the lump visible.
Why the PNL comparison matters: it is a self-contained check on your own positioning. Without it, a short PNL can be blamed on patient size or implant position when the real cause is failure to displace the implant far enough forward. If the PNL is short, reposition before you accept the image.
3. After three attempts the displaced view is still short, the implant keeps sliding back, and the patient is uncomfortable. What now?
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Stop escalating the maneuver and solve it differently.
Technique adjustments worth one more try:
- Have the patient lean forward or place her hand on the machine to relax the pectoralis; a tense subpectoral implant retracts.
- Use a wider hand placement along the inframammary fold rather than a single point of pressure, and pull tissue forward before applying the paddle.
- Try the MLO with a slight angle change or the patient standing rather than seated.
If it still fails:
- Do not force painful or repeated compressions on a small patient with implants.
- Acquire the best displaced and included views you can, then complete the study with targeted ultrasound of the palpable lump and the implant.
- Tell the radiologist directly that the posterior tissue is limited on the displaced views and why, and document it.
- Ensure the report states the limitation so a short PNL is not read as a negative posterior breast.
A documented limitation is honest; a mislabeled "complete" exam is not.