The Postoperative Breast




Do you see the branch that has been cut out on the left side of the tree in the picture? If the branch had been removed due to disease, where would you look to see if the disease had resurfaced? You would look really carefully at the remainder of that branch. You would also probably check the rest of the tree to be sure there was no new sign of disease in any other branches.


When imaging the patient with known or suspected breast cancer ( Chapter 17 ), we focused our attention on the affected ductal system to evaluate extent of disease. Likewise, when looking for recurrent cancer in women who have undergone breast-conserving therapy (BCT), we will focus on the ductal system where the cancer developed. We will start by looking at the lumpectomy scar and then within that ductal system.


In this chapter, we will review benign surgical changes and then turn our attention to detection of residual and recurrent breast cancer. We will give you our best tips for differentiating benign postoperative changes from those that may represent cancer.


Reduction Mammoplasty and Mastopexy


Reduction mammoplasty, mastopexy, and breast augmentation are typically performed by plastic surgeons rather than breast surgeons. Breast augmentation is discussed in Chapter 19 .


Reduction mammoplasty is performed to reduce the overall size of the breasts. It is often performed for women with back or shoulder problems due to the weight of large breasts. After mastectomy with reconstruction, the contralateral breast may be reduced to improve symmetry of breast size. Mastopexy, or a “breast lift,” is similar in surgical approach, but breast tissue is not removed. This is performed for women with ptotic breasts wishing to reverse the effects of living on a gravitational planet.


For both reduction mammoplasty and mastopexy, a keyhole incision is made ( Fig. 18-1 ). The scars of reduction mammoplasty are therefore seen primarily on the inferior breasts.




FIGURE 18-1


Keyhole Incision.

This incision is used for reduction mammoplasty and mastopexy. Incisions are made around the areola, at 4 and 8 o’clock, and along the inframammary fold ( blue lines ). For reduction, the fatty tissue and skin are removed from the inferior breast. For mastopexy, the skin is removed but not the underlying breast tissue. The skin is then pulled together leaving scars at 6 o’clock and along the inframammary fold. If the surgery stopped here, the nipple would now be under the breast mound because that tissue and skin have been removed. The plastic surgeon therefore makes a small incision at 12 o’clock, and the areola is moved cephalad.


The breast tissue has a “swirled” appearance in the inferior aspect of the mediolateral oblique (MLO) views—the ducts are heading toward the prior location of the nipple, which has been moved up to a perkier location ( Fig. 18-2 ). Isolated islands of breast tissue may be seen and are the result of separation of the tissue during surgery ( Fig. 18-3 ). Dermal calcifications are very common in the scar tissue ( Fig. 18-4 ). Oil cysts are also very common after both reduction and mastopexy ( Fig. 18-5 ).




FIGURE 18-2


Typical Changes of Reduction Mammoplasty.

Scars are present in the inferior breast ( arrows ), and the breast tissue has a swirled appearance on the MLO views ( open arrows ).



FIGURE 18-3


Isolated Islands of Breast Tissue.

Isolated islands of breast tissue ( arrow ) are common after reduction mammoplasty.



FIGURE 18-4


Dermal Calcifications in Reduction Scars.

Dermal calcifications in reduction scars ( arrows ) are present in the circumareolar area.



FIGURE 18-5


Palpable Oil Cysts.

Palpable oil cysts are seen following reduction mammoplasty ( arrows ).




Benign Surgical Biopsy


Surgical Biopsy Terminology


“Lumpectomy” literally means removal of a palpable lump. However, by convention, “lumpectomy” is used to describe the surgical removal of a cancer, regardless of whether or not it is palpable. “Excisional biopsy” refers to the surgical removal of an entire breast lesion. For example, a palpable fibroadenoma may undergo surgical excision. “Incisional biopsy” indicates a surgical biopsy in which only a portion of a lesion is removed. This type of biopsy may be performed when a core biopsy shows a high-risk lesion or was benign discordant. The goal of incisional biopsy is to obtain tissue for diagnosis rather than to completely remove a palpable finding or known carcinoma.


Changes of Surgical Biopsy


In the immediate postoperative period, small hematomas and seromas are common. Large fluid collections necessitating drainage are very uncommon. Fluid collections in the biopsy cavity decrease in size and have typically resolved by the time imaging is next performed. Imaging after a benign surgical biopsy may be helpful to confirm that the targeted lesion has been sampled or removed, but it is not required.


The first postoperative mammogram is often obtained 6 to 12 months after biopsy. Distortion from scarring will be worst on this earliest mammogram. The size and density of the scar will improve with time. Scars are planar ( Fig. 18-6 ). After about 5 years, distortion after benign biopsy becomes difficult to identify in most women. Significant architectural distortion more than 10 years after a benign biopsy is uncommon and should be viewed with suspicion. Don’t assume that the architectural distortion you see is due to a fibroadenoma that was removed in 1995! Comparison with older mammograms or diagnostic evaluation may be indicated.




FIGURE 18-6


Normal Benign Biopsy Scar.

The scar is planar, like a piece of paper. It appears linear on the exaggerated craniocaudal view ( arrow ) but is less dense and more diffuse on the MLO view ( arrow ). A wire ( open arrows ) has been placed on the skin to mark the scar in these and other images throughout this chapter.


Fat necrosis and benign dystrophic calcifications may evolve over the first year or two. The detritus of surgery may also be seen. Sutural calcifications may develop ( Fig. 18-7 ). A piece of retained hookwire may be seen occasionally ( Fig. 18-8 ).




FIGURE 18-7


Sutural Calcification ( arrow ).



FIGURE 18-8


Retained Hookwire.

Retained hookwire ( arrow ) after a wire-localized benign biopsy.




Surgery for Breast Cancer


Lumpectomy for Carcinoma


Imaging of women undergoing BCT is important for detecting residual disease in the early postoperative period (prior to radiation therapy [RT]), for identifying recurrent breast cancer after therapy, and for diagnosing metachronous breast cancer ( Box 18-1 ).



Box 18-1

Typical Post-BCT Imaging Protocol





  • Ipsilateral pre-RT mammogram (all calcification cases, others on a case-by-case basis)



  • Ipsilateral mammogram every 6 months for 2 to 3 years



  • Contralateral mammogram every year



  • Magnification views of the lumpectomy bed with each mammogram for 5 years




Residual Disease


There are several opportunities to identify residual disease in women undergoing BCT. These include positive or close margins of the excised specimen at pathologic examination, a specimen radiograph showing the lesion near the radiographic margin, and the pre-RT mammogram.


A pathology report of positive or close margins is associated with a high likelihood of cancer remaining in the breast. If the patient had calcifications associated with the cancer, magnification views of the operative region prior to re-excision may demonstrate concerning residual calcifications that can be localized as part of the re-excision surgery ( Fig. 18-9 ). These calcifications may be difficult to visualize because of the postoperative changes, so look back at the preoperative magnification views for comparison.




FIGURE 18-9


Positive Margin with Residual Calcifications.

A, Screening recall for a mass with associated calcifications. Core biopsy showed invasive ductal carcinoma (IDC) with ductal carcinoma in situ (DCIS). B, Specimen radiograph shows excision of the mass, though the posterior extent including calcifications may not be completely excised ( arrow ). DCIS was present at the margin. C, Magnification view after lumpectomy shows residual calcifications ( box ). These were wire localized to aid re-excision. D, Radiograph of the re-excision specimen documents removal (circle). Residual DCIS was present with negative margins.


Magnetic resonance imaging (MRI) is also very useful in assessing the amount of residual disease to assist decision making about whether another excision is likely to be successful ( Fig. 18-10 ). It can also detect additional previously occult lesions distant from the site of known tumor. When the MRI is abnormal ( Fig. 18-11 ), additional disease should be confirmed by biopsy before mastectomy is recommended. False-positive and false-negative MRI findings are fairly common; the sensitivity and specificity of MRI in identifying residual cancer in women with positive or close margins are 61.2% and 69.7%, respectively. A negative MRI does not indicate that the patient can forgo re-excision. Microscopic or nonenhancing carcinoma may still be present.




FIGURE 18-10


Normal Lumpectomy Cavity on MRI.

This patient had a close margin at lumpectomy. She desired breast conserving therapy. The T2 ( left ) shows the location of the seroma. The T1 postcontrast sequence ( right ) shows a thin rim of enhancement around the seroma. There is no imaging evidence of residual disease. She had successful BCT with low-volume re-excision.



FIGURE 18-11


Extensive Residual Disease on MRI.

This patient had a wire-localized removal of a small cluster of microcalcifications that were DCIS on core biopsy. Surgical margins were positive. The T2 sequence shows the left subareolar seroma. Postcontrast T1 sequence shows extensive nonmass enhancement in the medial left breast that represented residual noncalcified DCIS ( arrows ).


A pathology report of negative margins does not ensure that there is no residual disease present. Pathologic assessment of margins is an imperfect science; four to five small samples of tissue are taken from the areas that appear most suspicious for cancer on the surface of the lumpectomy tissue by gross inspection. Pathologists estimate that around 16% of the surface of a lumpectomy specimen is sampled for microscopic examination.


Radiologists have an opportunity to help; the specimen radiograph not only confirms whether the lesion was removed or not, but also where the lesion was located within the specimen ( Fig. 18-12 ). If the lesion is at or near an edge, the chance of incomplete excision is 79% to 98%. In these cases, communication with the surgeon in the operating room may guide immediate resection of the suspect margin. This can result in a negative margin, eliminating the need for additional surgery.




FIGURE 18-12


Mass at Edge of the Specimen.

Yes, the mass that is a biopsy-proven IDC has been removed, but it is located at the edge of the specimen. It is highly likely that the margin will be positive unless this situation is communicated to the surgeon so that additional tissue can be removed.


Radiologists have one more opportunity to identify residual disease: the pre-RT mammogram . In the early BCT trials, women with residual calcifications in or near the lumpectomy bed had a local recurrence rate of 60% compared with a 6% recurrence rate of women overall. That’s a huge difference, so we have a job to do! For women with breast cancer presenting as calcifications with or without an associated mass, an ipsilateral mammogram with magnification views prior to RT may identify residual calcifications in or near the lumpectomy bed ( Fig. 18-13 ). If a pre-RT mammogram is not obtained and residual carcinoma is identified after RT is administered, the patient must undergo mastectomy.


Aug 25, 2019 | Posted by in BREAST IMAGING | Comments Off on The Postoperative Breast
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