Introduction

Breast-reduction surgery is among the most applied plastic surgeries in the world (1). Such patients are subjected to some changes in their breast that mimic malignancy-related findings in radiologic examinations, thereby prompting invasive or surgical procedures. Mammography in itself is usually not sufficient in the diagnosis, as well as ultrasound. However, magnetic resonance imaging (MRI) are usually requested for confirmation and occasionally lesions should be confirmed histopathologically with a biopsy (2,3). Fat necrosis in breast can occur as a result of previous breast surgery (lumpectomy, reduction, augmentation), radiotherapy, anticoagulant therapy, trauma, Weber-Christian disease, granulomatous angiopanniculitis and polyarteritis nodosa (4-6). Fat necrosis in breast can sometimes be difficult to distinguish from a malignant lesion.

Breast fat necrosis is a common benign condition that can cause a wide variety of mammographic findings such as tissue lumps, calcifications, fatty cysts and localized skin thickening (7). There are various clinical and imaging features where fat necrosis is sometimes not easy to distinguish from malignancy and can even be asymptomatic (8). In addition, the doctor can sometimes detect pathological condition by mammography only (9,10). To prevent biopsy, the mammographic spectrum of fat necrosis appearances must be recognized.

There are only limited number of studies in the literature that evaluate the clinical and radiological findings in long-term patient follow-up after breast reduction surgery. Therefore, we aimed to emphasizing the importance of radiological imaging in the long-term follow-up of patients who have undergone breast reduction surgery.

Methods

We examined the preoperative and postoperative findings (breast examinations and radiological imaging) in 21 patient files who underwent mammaplasty between January 2014 and January 2019. The study approval was obtained by University of Health Sciences Turkey, İstanbul Training and Research Hospital Ethical Committee (approval number: 2660, date: 08.01.2021). Informed consents were equally received from all the patients.

The superomedial pedicle technique was performed in 19 patients, inferior pedicle in 1 patient and free nipple technique in 1 patient. Prior to the surgery, mammographies and ultrasounds were performed for screening purposes and no pathological findings were found.

Detailed breast examination, bilateral breast ultrasonography (US) and mammography were requested for preoperative follow-up as well as for long-term annual follow-up of 21 patients in the study. Breast MR was requested in 9 patients with suspicious lesions. One patient eventually underwent a cyst excision and tru-cut biopsy, which revealed no malignant lesions.

In ultrasonographic examinations, both breasts and axilla were examined on different planes using a broadband linear probe of 10-14 MHz (Toshiba Aplio 500, Minato, Tokyo, Japan). MRI examinations of cases with 1.5 Tesla MRI devices (GE Healthcare Signa HDi 1.5T, General Electric Medical Systems, Boston, MA, USA) were performed in the prone position with the breast coil. In all examinations, axial T1AG, fat-pressed axial and sagittal T2AG, diffusion-weighted and axial-plan fat-saturated T1-weighted dynamic contrast images were taken. Before the patient was taken into the MRI device, a catheter was inserted into the antecubital vein for the injection of the contrast agent.

Statistical Analysis

Descriptive analysis was performed using GraphPad Prism 7.0 software (GraphPad Software, Inc., La Jolla, CA, USA).

Results

The average age of the participants was 42.9±12 years (range: 20-58). Table 1, 2 reveal amongst others: The surgical technique, amount of breast resection, and the sternal notch-nipple areolar complex distance. Table 3 reveals clinical characteristics such as current diseases of participants, use of drugs and smoking. Histopathological examination of resected materials of all patients revealed no abnormalities. Scar revision surgery was performed in 2 patients (9.52%). In another patient, a suspicious tender mass was found during physical examination two years after surgery. Tru-cut biopsy accompanied by ultrasonography was then performed and was compatible with fat necrosis. Fat cyst excision was performed in this patient and a malignancy was ruled (Table 4).

Postoperative radiological findings from all three imaging modalities included parenchymal distortion (n=11; 52.3%), rough calcifications (n=8; 38.0%), fat cyst (n=7; 33.3%), focal fibrosis (n=6; 28.5%), fat necrosis (n=5; 23.8%), nipple retraction (n=5; 23.8%), malignant-like peripheral contrast (n=3; 14.2%), nodular lesions (n=1; 4.7%), malignant-like distortion (n=1; 4.7%) and fluid collection with skin thickening (n=1; 4.7%) (Table 5, Figure 1, 2, 3, 4, 5, 6, 7, 8). The most common MRI findings were parenchymal distortion and asymmetry, malignant-like contrast, nipple retraction, focal fibrosis, postoperative fluid collection and fat necrosis.

In mammography, fat necrosis was generally seen as coarse dystrophic calcifications. In some cases, calcifications were heterogeneous and biopsy was required for definitive diagnosis. In MRI, a fat necrosis could be perceived as a malignant-like distortion and mass-like appearance. MR contrast enhancement was seen in the periphery, especially in the early period following surgery and in cases of inflammation.

This enhancement pattern is also observed in malignant tumors, especially in the presence of necrosis. In fat necrosis, suppression of central areas in T1WI in hyperinstense and fat saturated series is typical and important in differential diagnosis (Figure 7) (11-17).

Discussion

Parenchymal tissue changes such as fat necrosis, fibrosis, scaring, which occur in imaging after a mammaplasty can mimic malignancies. If mammography or ultrasonography is not sufficient to differentiate these lesions from malignancy, MRI or histopathological verification with the biopsy is critical (2). The accurate recognition of the radiologic findings related to surgery in the postoperative period after a mammaplasty is key in distinguishing benign and malignant lesions.

The most common radiological findings in this period include asymmetric reposition of the remaining parenchyma tissue, nipple elevation, common parenchymal calcifications, fat necrosis and cysts, retroareolar fibrotic bands, thickening of the skin and postoperative local fluid collections. In these patients, fat necrosis is the finding with the most similar properties as malignant tumors. Kim et al. (11) revealed that the most frequent mammographic finding of the reduction mammoplasty was nipple elevation (84.3%). Other findings included retraction of the lower breast (80%), thickening of the skin (78.6%), downward shifting of the glandular tissue (47.1%), retro-areolar fibrotic band (42.9%), and areolar skin calcification or lipid cyst (35.7 %) (11).

Fat necrosis is often iatrogenic. It is seen in breasts that have undergone surgery and radiotherapy. The most common locations are subareoalar and periareolar regions, but they can also develop in other areas. In our patients, we found that fat necrosis was most commonly located in close proximity to the pedicle. This is due to limited vascularization in this area. Irregularly bounded lesions caused by fat necrosis can mimic breast cancer by causing thickening, withdrawal and parenchymal distortion on the skin. This is an issue especially in patients undergoing surgery or radiotherapy (18,19). Signs of fat necrosis in ultrasonography; solid, semisolid, oval, lobular mass with irregular edges or subcutaneous irregular hyperechoic lesions can be seen. Parenchymal distortion due to fibrotic, inflammatory, and calcified lesions can also be observed. Apart from that, it could be in the form of an anechoic mass with a simple cyst or posterior acoustic shading (18-21).

Long-term MRI findings due to fat necrosis can be fat cysts that hold round contrast. Fat necrosis can also be seen as heterogeneous hyperintense lesions in T1A views, and as heterogeneous hypointense lesion and an irregular or round mass after intravenous gadolinium injection in T2A views (2,22). Isointense parenchymal contrast pattern can be seen as a peripheral ring or nodule. In kinetic studies, the pattern of contrast specific to fat necrosis is unclear (22).

Another finding that can mimic malignancy is focal fibrosis from the proliferation of fibrous connective tissue surrounding ducts and acinus. Radiologically, we observe parenchymal distortion, irregularly-bounded oval and spicule-shaped lesions can be seen. Since these findings are similar to malignancy, it is necessary to perform biopsy for definitive diagnosis if there is no history of surgery, trauma, radiotherapy (19,21,23).

To avoid biopsy, it is necessary to properly define the spectrum of fat necrosis. There are no comprehensive studies to classify the postoperative changes of patients who have undergone a reduction mammaplasty. The role of ultrasonographic evaluation is evolving with technical developments. With high resolution ultrasonography, malignancies can often be discriminated (2). MRI is not a routine diagnostic method in the diagnosis of breast lesions but can be used in the presence of lesions that cannot be diagnosed by other radiological methods (19). Fat necrosis can still be difficult to diagnose, and in some cases, diagnosis is done with a tru-cut biopsy.

Study Limitations

This study has several limitations. First, it was a retrospective study and the patients were recruited from a single-center. Standardization of participants was not optimal and future prospective randomized studies could overcome these limitations.

Conclusion

Physicians need to adequately inform patients about the need for future ultrasound and biopsy after surgery. Moreover, the characteristics of palpable nodules and radiological findings after a mammaplasty require exploration in order to differentiate other lesions from malignant ones. Furthermore, patient check-up should be carried out systematically with a team consisting of a radiologist, plastic surgeon, and an oncologist, and they should be advised to continue their routine breast cancer screening.

Ethics Committee Approval: The study approval was obtained by University of Health Sciences Turkey, İstanbul Training and Research Hospital Ethical Committee (approval number: 2660, date: 08.01.2021).

Informed Consent: Informed consents were equally received from all the patients.

Peer-review: Internally peer-reviewed.

Authorship Contributions: Surgical and Medical Practices - G.T., D.A., M.S.; Concept - G.T., D.A., M.A.N., M.S.; Design - G.T., D.A., M.A.N., M.S.; Data Collection or Processing - G.T., D.A., M.S.; Analysis or Interpretation - D.A., M.A.N.; Literature Search - D.A., M.A.N.; Writing - G.T., M.S.

Conflict of Interest: No conflict of interest was declared by the authors.

Financial Disclosure: The authors declared that this study received no financial support.