A mimic of breast carcinoma 1-year post vacuum-assisted excision of a benign breast lesion

Abstract

A 64-year-old woman underwent vacuum-assisted excision (VAE) for a biopsy-proven radial scar in the right breast detected during screening mammography. A follow-up mammogram was performed at 1 year following multidisciplinary team discussion. This demonstrated a 1 cm mass adjacent to the biopsy clip at the site of the prior VAE. A repeat biopsy of the mass was performed which revealed benign scar tissue. This is the first reported case of post-VAE scar tissue mimicking breast carcinoma on mammography.

Background

Vacuum-assisted excision (VAE) is a relatively new technique in managing B3 breast lesions. The long-term imaging appearances following this procedure are not yet fully known. We present an interesting case, 1-year post VAE, with a mass-like appearance at the previous VAE site mimicking breast carcinoma

Case presentation

A 64-year-old woman was recalled following a screening mammogram in November 2016 for further evaluation of a subtle area of architectural distortion in the upper outer quadrant of her right breast (figure 1). The mammogram also demonstrated multiple bilateral fibroadenomata. Digital breast tomosynthesis (figure 2) was performed at the time of assessment which confirmed the presence of architectural distortion in the upper outer right breast with no associated mass or calcification (BI-RADS 4). Targeted ultrasound was normal (figure 2). Core biopsy was performed using tomosynthesis and a tissue marker clip was placed. Histological examination of the core biopsy demonstrated a radial scar with no associated atypia (category B3a).

Figure 1.

Screening mammogram. Craniocaudal (CC) (A) and mediolateral oblique (MLO) (B) views. There is an area of subtle architectural distortion in the outer right breast (arrows). There are also multiple fibroadenomas.

Figure 2.

(A) Normal ultrasound. (B) Digital breast tomosynthesis C-view (CC) demonstrating architectural distortion in the outer right breast without calcifications or associated mass. (C) Post vacuum-assisted excision (VAE) mammogram (CC) demonstrating clip at the site of VAE.

The findings were reviewed at the multidisciplinary team meeting (MDT). A decision was made to recommend VAE rather than open diagnostic excision. VAE was performed in December 2016 using tomosynthesis. The tissue marker clip placed at the time of original biopsy was removed and a new clip was placed (figure 2). The procedure was well-tolerated by the patient and there were no complications. The VAE specimen weighed 4 g and histopathological examination revealed residual radial scar and core biopsy change. There were no atypical changes and no evidence of malignancy. The patient’s imaging and histopathological findings were further reviewed at MDT and a decision was made to perform mammographic follow-up in 1 year.

In November 2017, follow-up mammogram demonstrated a 1 cm mass with spiculated margins adjacent to the tissue marker clip in the upper outer right breast (figure 3). Digital breast tomosynthesis and ultrasound were performed (figure 4) revealing a mass-like lesion at the site of prior VAE (BIRADS-4). Ultrasound-guided core biopsy was performed and a tissue marker clip was placed. Histopathological examination demonstrated densely hyalinised stroma containing haemosiderin, chronic inflammatory cells and foreign body giant cells arranged around refractile material. The appearances were consistent with scar tissue with no evidence of malignancy.

Figure 3.

Screening mammogram 1-year post vacuum- assisted excision. A (CC) and B (MLO) demonstrate a mass with irregular margins adjacent to the biopsy clip in the outer right breast.

Figure 4.

(A) Digital breast tomosynthesis synthetic C-view 1-year post vacuum- assisted excision (VAE) revealing an irregular mass at the site of VAE in the outer right breast. (B) Ultrasound right breast 1-year post VAE revealing a mass-like lesion at the excision site.

Outcome and follow-up

The patient’s case was again discussed at the MDT. As the results of the core biopsy were benign, no follow-up intervention was required. A decision was made to perform a follow up mammogram after 1 year. This demonstrated stable mammographic appearance with post-VAE scarring and no evidence of malignancy, confirming the findings at biopsy 1  year prior (figure 5).

Figure 5.

Screening mammogram 2 years post vacuum- assisted excision (VAE) A (CC) and B (MLO). Unchanged mass-like scarring at the site of VAE. No evidence of interval malignancy confirming the benign findings on biopsy 1 year prior.

Discussion

VAE is a relatively novel technique used in breast diagnostics and in the further workup and management of certain benign and atypical breast lesions.¹ A single large bore needle is inserted into the breast under ultrasound or tomographic guidance. The vacuum technology draws breast tissue into the needle and, using a rotating cutting device, multiple samples of tissue are taken through the same needle. The tissue is then weighed to ensure that an adequate sample (minimum 4 g) has been acquired and a radio-opaque marker clip is inserted into the breast for future reference.^2–4

VAE is predominantly indicated for further sampling of B3 lesions.^{5 6} A lesion is designated as B3 when there is a risk of accompanying malignancy or upgrade to a more advanced lesion when additional tissue is examined. Many of these lesions would otherwise require surgical excision with associated morbidity and cost, or close surveillance with follow-up imaging causing anxiety to the patient.⁶ The decision to recommend VAE is undertaken by the MDT and is frequently the only additional procedure that is required. There is currently no established consensus regarding follow-up if no malignancy has been detected although the United Kingdom National Health Service National Breast Screening Program recommends annual follow-up for 5 years if there is atypia on the original biopsy or VAE.⁷ Long-term follow-up data are required to further inform surveillance strategy.

Benign breast lesions may mimic carcinoma mammographically⁸ and sonographically.⁹ Typical mimics include fat necrosis, scar, diabetic mastopathy, fibrocystic changes, sclerosing adenosis, ruptured inflammatory cysts, inflammatory abscesses, granulomatous mastitis and fibroadenomata. This is the first report of radiological imaging 1-year post VAE that demonstrated findings that mimicked a breast carcinoma. VAE is a relatively new technique and this case illustrates that post-VAE scarring may present with imaging appearances similar to that of malignancy. MRI can help differentiate scar tissue from malignancy; however, frequently access to MRI can be limited, and this was not employed in this case.

Learning points.

• Vacuum-assisted excision (VAE) is a relatively new technique which can be both diagnostic and therapeutic in the management of small breast lesions.

• There is limited experience in the long-term imaging appearances in this cohort.

• This case demonstrates that although scarring post VAE may be expected, we should be aware that it can be very marked and mimic tumour.