Delayed development of enhancement in fat necrosis after breast conservation therapy: a potential pitfall of MR imaging of the breast

Usefulness of postoperative surveillance MR for women after breast-conservation therapy: Focusing on MR features of early and late recurrent breast cancer

Purpose

To investigate the imaging characteristics of early and late recurrent breast cancer and the detectability of mammography, ultrasonography, and breast magnetic resonance imaging (MRI) in patients who underwent breast-conservation therapy (BCT).

Materials and methods

Total of 1312 women with 2026 surveillance breast MRI after BCT between January 2014 and September 2018 were studied. Early recurrence was defined as newly diagnosed breast cancer and/or axillary metastasis within 12 months of surgery. Late recurrence was defined as recurrence after 12months of surgery. We assessed the detectability of recurrent lesions in each postoperative imaging modality and evaluated characteristics of recurrent lesions on postoperative MRI by comparing early and late recurrence groups.

Result

Of the 2026 cases, 103 were confirmed as recurrent breast cancer by biopsy or surgery. Thirty-one cases were early recurrence, and 72 cases were late recurrence. MRI showed significantly higher detectability for recurrent lesions (102 cases, 99%) than mammography (59.4%, p < 0.001) or ultrasound (68.9%, p < 0.001), or both mammography and ultrasound (81.6%, p < 0.001). The recurrent lesions did not have typical malignant morphologic features, but variable features on MRI. However, early recurrent lesions showed fast enhancement in early dynamic phase regardless of the kinetic pattern of delayed dynamic phase; and late recurrence lesions showed early fast enhancement and delayed washout pattern. There were 19 cases which were not detected on mammography or ultrasound but could only be detected with MRI.

Conclusion

Postoperative breast MRI showed significantly higher detectability for recurrent lesions than mammography and ultrasound. Early fast enhancement is the most important feature of recurrent lesions on postoperative breast MRI for both early and late recurrence groups. Due to its high possibility of recurrence, further work-up should be considered regardless of their morphologic features.

Natural course of fat necrosis after breast reconstruction: a 10-year follow-up study

Background

Although fat necrosis is a minor postoperative complication after breast reconstruction, occasionally it mimics to tumor recurrence in patients with breast cancer. Therefore, the surgeon should distinguish between benign fat necrosis and true local recurrence. The authors evaluated the clinical characteristics of fat necrosis after breast reconstruction and investigated the natural course of fat necrosis.

Methods

Between 2007 and 2013, a total of 362 patients underwent breast reconstruction after partial or total mastectomy for breast cancer in Kyungpook National University Hospital. Clinicopathologic characteristics and the occurrence of fat necrosis were assessed during surveillance for 10 years of mean follow-up period.

Results

There were 42 cases (11.6%) of fat necrosis after breast reconstruction with partial or total mastectomy which were confirmed by needle or excision biopsy. The fat necrosis was resolved after a mean period of 45.9 months (SD, ± 42.1) and 26 cases (61.9%) of fat necrosis were almost completely resolved (less than 5 mm) during 10-year follow-up period.

Conclusion

Based on the natural course of fat necrosis, the fat necrosis after breast reconstruction can be only monitored, if pathologic confirmation was done. More than half of the cases will be resolved within 2–3 years.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-07881-x.

Radiologic-Pathologic Correlation for Benign Results After MRI-Guided Breast Biopsy

OBJECTIVE

The majority of MRI-guided breast biopsies yield benign pathology. The purpose of this article is to provide a comprehensive overview of benign pathologic entities commonly encountered at MRI-guided breast biopsy.

CONCLUSION

Proper radiologic-pathologic correlation is an integral component of MRI-guided breast biopsy. Familiarity with the spectrum of MRI findings and key histopathologic features of common benign entities will enhance the radiologist's confidence in determining concordance and lead to improved patient management recommendations.

Diagnostic performance of CT attenuation values of focal 18F-FDG avid breast lesions detected on whole-body PET-CT in postoperative breast cancer patients

To assess whether CT attenuation values help in differentiating benign from malignant etiology of focal (18) F-FDG avid breast lesions detected on whole-body PET/CT exam in postoperative breast cancer patients. Institutional review board approval and waived informed consent were obtained for this HIPAA-compliant retrospective study. Between January 2009 and July 2011, a total of 85 patients had 97 focal (18) F-FDG avid breast lesions on whole-body PET/CT. Of these, 54 (56%) lesions were biopsy-proven primary invasive breast carcinoma that had not undergone treatment at the time of PET/CT, 35 (36%) were benign lesions, and 8 were locally recurrent breast carcinoma. Mean attenuation values were retrospectively measured in Hounsfield units (HU) for the correlative lesion on the CT portion of the exam. Receiver-operating characteristic curves (ROC) were calculated to determine the optimal cutoff values of HU that would best discriminate between benign and malignant lesions. Interobserver agreement for measured mean attenuation values was assessed by calculating the intraclass correlation coefficient (ICC). Mean HU for the benign lesions group and the local recurrence lesions group was -11.0 ± 30.3 versus 32.9 ± 6.87 (p < 0.0002). ROC curve analysis comparing benign breast lesions to local recurrence lesions found an optimal cutoff value of 17 HU (area under curve = 0.982, p < 0.0001, Sensitivity = 100%, Specificity = 89%). ICC with regard to interobserver agreement in measuring the mean HU of the benign lesions was 0.84 (95% confidence interval 0.64-0.93) and for the malignant lesions was 0.88 (95% confidence interval 0.77-0.94). A CT attenuation threshold value of less than 17 HU suggests benign etiology of focal (18) FDG avid breast lesions in postoperative breast cancer patients. If confirmed by additional studies, these findings may provide additional information to guide the treating physician regarding decisions for supplementary imaging or the need to biopsy.

Magnetic resonance imaging and ultrasound evaluation after breast autologous fat grafting combined with platelet-rich plasma

BACKGROUND

Breast lipofilling is a fairly simple and safe procedure if it is performed by experienced surgeons.

METHODS

The authors evaluated the radiologic findings from 24 breasts (15 women) subjected to a lipofilling procedure (two sessions) for corrective surgery or cosmetic reasons. Mammography, ultrasound, and magnetic resonance imaging were performed before the first lipofilling session (T0) and 12 months after the last session (T12); ultrasound and magnetic resonance imaging were used 3 months after the first session (Ti) and 3 and 6 months after the last session (T3 and T6). Volumetric evaluations were also made through three-dimensional magnetic resonance imaging reconstruction.

RESULTS

Ultrasound showed oily cysts in 66.67 percent of the breasts at Ti, 70.83 percent at T3, 62.5 percent at T6, and 45.83 percent at T12, whereas magnetic resonance imaging detected oily cysts in 8.33 percent at Ti and T3 and T6 months and 4.17 percent at T12. At Ti, T3, and T6, the cytosteatonecrotic areas identified on both ultrasound and magnetic resonance imaging were unchanged (8.33 percent), whereas at T12 those cytosteatonecrotic areas were increased on ultrasound (12.5 percent) and even more on the magnetic resonance imaging scans (16.67 percent). The average resorption percentage of injected volume was 15.36 percent at T6 months and 28.23 percent at T12 months.

CONCLUSIONS

Postlipofilling breast changes can be distinguished from malignant alterations by experienced radiologists and need not interfere with early cancer diagnosis if patients are checked regularly. Moreover, magnetic resonance imaging is very useful for breast volume assessments and for detecting possible changes during longitudinal study.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Traumatic fat necrosis of male breast

Fat necrosis is a benign nonsuppurative inflammatory process that most commonly occurs in female breast. It is a rare condition in male breast. There are very few reports in the literature. There is a wide range of manifestations of fat necrosis and can mimic breast cancer clinically and radiologically. We report a case of fat necrosis of the breast in a 57-year-old man.

First description of MR mammographic findings in the tumor bed after intraoperative radiotherapy (IORT) of breast cancer

The aim was to investigate changes in the tumor bed on magnetic resonance mammography (MRM) after intraoperative radiotherapy (IORT) and whether they would limit the diagnostic value of posttherapeutic MRM. We retrospectively investigated 36 patients undergoing MRM after IORT (median interval 2.8 years, range 0.4-7.1). Wound cavities with fat necrosis were common after IORT (81%). They were associated with persisting contrast enhancement, i.e., enhancement was mostly seen irrespective of the posttherapeutic interval. It normally presented as rim enhancement and did not cause any diagnostic uncertainty if viewed together with other tissue characteristics. We do not expect a limited diagnostic value of MRM after IORT.

Fat necrosis may mimic local recurrence of breast cancer in FDG PET/CT

Fat necrosis of the breast is a benign condition that most commonly occurs as the result of trauma. The radiographic and clinical significance of fat necrosis of the breast is that it may mimic malignancy. We present a case of false positive FDG PET/CT scan caused by fat necrosis and mimics local recurrence of breast carcinoma 3 years after radical mastectomy. Physicians must be aware of fat necrosis as a potential pitfall for PET/CT. Fat necrosis must be considered in the differential diagnosis of hypermetabolic breast masses in patients who previously had mastectomy or mammoplasty.

MRI of fat necrosis of the breast: the "black hole" sign at short tau inversion recovery

OBJECTIVE

To describe MRI features of fat necrosis of the breast.

MATERIALS AND METHODS

Twenty-five lesions in 16 patients were retrospectively analyzed. MRI was performed due to equivocal findings at conventional imaging after surgical treatment of cancer (n=14) or during anticoagulant therapy (n=1), after focal mastitis treated with ductal resection (n=1). In the 15 patients with previous surgery MRI was performed after a median interval of 24 months, using short tau inversion recovery (STIR) and contrast-enhanced dynamic T1-weighted sequences. Signal-to-noise ratio (SNR) inside the lesion and surrounding healthy fat was calculated on both STIR and unenhanced T1-weighted images. Maximal lesion diameter was measured on STIR images. All lesions had final clinical and imaging assessment in favor of fat necrosis and negative clinical and imaging follow-up (21-40 months; median 24 months).

RESULTS

At STIR sequence, fat necrosis appeared as a "black hole", being markedly hypointense (median SNR=29) compared with surrounding fat (median SNR=95) (P<0.001), while no significant difference was found at unenhanced T1-weighted sequence. No significant correlation with time from treatment was found. Of 25 lesions, 15 showed ring enhancement, with continuous increase (n=10), plateau (n=2), or wash-out curve (n=3). The 11 enhancing lesions in the 8 patients with previous radiation therapy showed an initial enhancement higher than that of the 4 enhancing lesions in the 2 patients who did not, although the difference was not significant (P=0.104).

CONCLUSION

Fat necrosis of the breast exhibits a "black hole" sign on STIR images, allowing for an easier diagnosis in clinical practice.

[Diffusion-weighted MR imaging of the breast]

Diffusion-weighted imaging is helpful to further characterize lesions that remain indeterminate after morphological and dynamic MR evaluation. Suspicious lesions are hyperintense on diffusion-weighted images with corresponding low ADC values, indicating restricted diffusion and hypercellularity. Benign lesions and tumors responding to treatment usually have no diffusion restriction. ADC maps are useful for T2W hyperintense lesions that could mask the presence of restricted diffusion. Image fusion is sometimes needed to accurately localize enhancing lesions on ADC maps. For indeterminate lesions, a hypocellular appearance suggests a lower ACR category whereas the presence of restricted diffusion suggests a higher category.

The great mimicker: fat necrosis of the breast--magnetic resonance mammography approach

Fat necrosis of the breast is a common benign inflammatory process resulting from injury to breast fat. The pathogenesis of fat necrosis helps to explain its imaging features, which range from benign to malignant-appearing findings. This article reviews the role of magnetic resonance mammography and other conventional imaging techniques in the differential diagnosis of fat necrosis.

The many faces of fat necrosis in the breast

OBJECTIVE

This article describes the manifestations of fat necrosis on mammography, sonography, and MRI and correlates the imaging findings with the pathologic findings.

CONCLUSION

On imaging studies, the appearance of fat necrosis ranges from typically benign to worrisome for malignancy. Mammography is more specific than sonography, and emphasis should be placed on mammography in making the diagnosis of fat necrosis. In selected cases, MRI may be helpful in showing findings consistent with fat necrosis.

Optimal clustering of kinetic patterns on malignant breast lesions: comparison between K-means clustering and three-time-points method in dynamic contrast-enhanced MRI

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is useful for breast cancer diagnosis and treatment planning. Nevertheless, due to the multi-temporal nature of DCE-MRI data, the assessment of early stage breast cancer is a challenging task. In this study, we applied an unsupervised clustering approach and cluster validation technique to the analysis of malignant intral-tumoral kinetic curves in DCE-MRI. K-means cluster analysis was performed from real world malignant tumor cases and the data were transformed into an optimal number of reference patterns representative each cluster. The optimal number of clusters was estimated by a cluster validation index, which was calculated with the ratio of inter-class scatter to intra-class scatter. This technique then classifies tumor specific patterns from a given MRI data by measuring the vector distances from the reference pattern set, and compared the result from the k-means clustering with that from three-time-points (3TP) method, which represents a clinical standard protocol for analysis of tumor kinetics. The evaluation of twenty five cases indicates that optimal k-means clustering reflects partitioning intra-tumoral kinetic patterns better than the 3TP technique. This method will greatly enhance the capability of radiologists to identify and characterize internal kinetic heterogeneity and vascular change of a tumor in breast DCE-MRI.

Ultrasound and MRI findings in appendicular and truncal fat necrosis

OBJECTIVE

The objective was to evaluate ultrasound and MRI in clinical appendicular and truncal fat necrosis.

MATERIALS AND METHODS

Thirty-three patients (14 men, 19 women, median age 55, range 29-95) were retrospectively evaluated. Histologically, three groups were seen: Group 1 (n = 18) consisted of patients with subcutaneous masses with septal and extrinsic oedema; in Group 2 (n = 11) necrosis occurred within lipomatous tumours and little oedema; and in Group 3 (n = 4) there were large complex masses consistent with Morel-Lavallée lesions. Two experienced radiologists reviewed MR (n = 30) and ultrasound (n = 32) images with consensus agreement. MRI was performed on a 1.5T system with T1-weighted, T2-weighted fat-suppressed and T1-weighted fat-suppressed post-intravenous gadolinium sequences obtained in two orthogonal planes. Ultrasound (linear 5- to 13.5-MHz probe) was performed in the longitudinal and short axis. Anatomical position, size, shape (oval, linear, ill-defined), internal architecture (lobules, septi or stranding), intrinsic signal characteristics, presence of surrounding pseudocapsule, extrinsic linear stranding and vascularity (gadolinium enhancement or power Doppler) were recorded.

RESULTS

Anatomical locations were buttock/thigh (n = 17), leg (n = 6), upper limb (n = 5) and thoracic/abdominal wall (n = 5) with the majority of lesions (30 out of 33) oval/linear in shape. On ultrasound and MRI most lesions showed internal fat lobules, intervening septi and a surrounding pseudocapsule.

CONCLUSION

Fat necrosis can usually be identified as containing multiple fat lobules on ultrasound and MRI despite a varying degree of inflammatory change surrounding and within the mass.

[Radiological evaluation after lipomodelling for correction of breast conservative treatment sequelae]

Breast lipomodelling has been used in our unit since 2002 to correct the sequelae of conservative treatment of cancer. Morphologically, satisfactory results have been recorded and the method is likely to develop considerably. However, the technique has also been questioned because of the possible deleterious radiological impact of injecting fat into the breast. The present work investigated the radiological aspect of conserved breast reconstructed by lipomodelling in a series of 21 patients undergoing ultrasound examination, mammography and MRI, before and after the procedure. Benign-looking microcalcifications were detected on 19% of the mammographies, small (<1cm) oily cysts and complex cysts were visible on respectively 57 and 19% of ultrasound images, whereas 47% of the MRI scans indicated cytosteatonecrotic lesions. Even though multiple events could be observed, their frequency is close to that observed following other conventional breast surgery. Besides, there is clear radiological evidence of benignity. The conclusion of the study is that images obtained after lipomodelling are satisfactory and in no way suggestive of recurrence of breast cancer. Provided that radiologists and experts are aware of this pattern, there is no impact on the radiological follow-up of the patients.

Fat necrosis of the breast—A review

Fat necrosis of the breast is a benign condition that most frequently affects peri-menopausal women. It can mimic breast cancer clinically or radiologically. In other cases it can obscure malignant lesions. The core of this review is derived from a MEDLINE database literature search from 1966-2004. Further references were from lateral search. In this paper, we review the pathogenesis and pathology clinical and radiological features of fat necrosis of the breast. The implication of fat necrosis in the management of patients with breast lump is also discussed. Fat necrosis of breast is a complex process. Therefore, a systematic review of this condition will enable surgeons, radiologists and oncologists working in the field of breast disease to understand it better and improve its management.

[Architectural distortion and diagnostic difficulties]

Identification of architectural distortion requires a good practice of mammography. Prevalence is estimated at 6% of detected abnormalities in screening programs. Under this denomination are gathered focal architectural distortion with predictive positive value (PPV) of 10% and stellate images without central densification, which are more suspicious (PPV 50%). In order to establish a diagnosis, false images must be eliminated by other views. Minimal architectural distortion have to be investigated by other techniques (sonography, MRI percutaneous biopsy) in order to define the best strategy for further management. Stellate images suggestive of radial scars must be surgically removed. The relationships between radial scars and tubular carcinoma are discussed. A particular attention is required for post traumatic or post surgical scars if it exist a high risk of local recurrence or controlateral carcinoma specially after conservative or oncoplastic surgery.

Contrast-Enhanced High-Resolution MRI of Invasive Breast Cancer:Correlation with Histopathologic Subtypes

OBJECTIVE

We sought to determine whether contrast-enhanced MRI could aid in the identification of the histopathologic subtypes of invasive ductal carcinoma.

MATERIALS AND METHODS

We evaluated the contrast-enhanced MR images obtained in 62 women with invasive ductal carcinoma of no special type. The presence or absence of three distinct MRI findings-linear enhancement, a serrated border, and delayed rim enhancement-was evaluated. Classification and regression tree analyses were performed to construct the most efficient algorithm for predicting histopathologic subtype on the basis of dynamic MRI features.

RESULTS

Histopathologic subtypes of the invasive ductal carcinomas were scirrhous carcinoma in 22 patients, solid tubular carcinoma in 14, and papillotubular carcinoma in 26. A lesion with a serrated border was observed in 28 (45.2%) of the 62 patients. Delayed rim enhancement was seen in 23 (37.1%) and linear enhancement in 20 (32.3%). Scirrhous carcinomas were closely associated with a serrated border (20/22 or 90.9%, p < 0.0001). Delayed rim enhancement was frequently observed in solid tubular carcinomas (12/14 or 85.7%, p < 0.0001) but was not typically seen in scirrhous carcinomas (1/22 or 4.5%, p < 0.0001). Linear enhancement showed relatively high prevalence in papillotubular carcinomas (13/26 or 50%) and low prevalence in solid tubular carcinomas (1/22 or 7%, p < 0.02). Histopathologic subtypes of invasive breast carcinoma of no special type could be correctly identified in 47 (75.8%) of 62 lesions using the diagnostic algorithm generated by the classification and regression tree analyses.

CONCLUSION

MRI features showed a close relationship with histopathologic subtypes of invasive ductal carcinoma of no special type. Contrast-enhanced MRI can be a noninvasive diagnostic tool for histopathologic subtypes of invasive breast cancer.

Breast Reconstruction with a Transverse Rectus Abdominis Myocutaneous Flap: Spectrum of Normal and Abnormal MR Imaging Findings

The authors retrospectively reviewed their clinical database for cases of breast magnetic resonance (MR) imaging performed in women who had undergone breast reconstruction with a transverse rectus abdominis myocutaneous (TRAM) flap. Patient histories, MR imaging results, and, when available, biopsy results were reviewed. During a 4-year period, 24 neobreasts were imaged in 22 women who had undergone TRAM flap reconstruction after mastectomy. In most of the cases (64%), the indication for MR imaging was a palpable abnormality or pain. In four of 24 cases (17%), recurrent breast cancer was detected. These cases consisted of a local chest wall tumor (n = 2), an infiltrating chest wall tumor (n = 1), and axillary nodal recurrence (n = 1). In all four cases, MR imaging demonstrated a suspicious lesion or abnormality. In 11 of 24 cases (46%), benign findings only were demonstrated. These consisted of localized or diffuse skin thickening, fibrosis, fat necrosis, and seroma. In nine of 24 cases (38%), no pathologic abnormality was identified. MR imaging is useful in detection of locally recurrent tumor in patients who have undergone breast reconstruction with a TRAM flap. MR imaging allows differentiation between benign and malignant findings in patients with palpable abnormalities or pain after TRAM flap reconstruction.

Fat necrosis of the breast: mammographic, sonographic, computed tomography, and magnetic resonance imaging findings

Fat necrosis of the breast is a benign inflammatory process that may be mistaken for cancer in clinical examination or imaging studies. Although its mammographic manifestations are well known, data from other imaging modes, particularly sonography and magnetic resonance imaging, are limited. With the growing number of breast surgeries performed today (eg, breast-conserving, autologous tissue reconstruction, mammoplasty), fat necrosis is seen more often in daily practice. Knowledge of its imaging features could improve clinical management, including the avoidance of unnecessary biopsy procedures. The main objectives of this article are to review the literature and to relate the manifestations of fat necrosis on mammography, sonography, magnetic resonance imaging, and computed tomography to their associated histopathologic events.

Fat necrosis of breast: a potential pitfall in breast MRI

Fat necrosis is a benign nonsuppurative inflammatory process of adipose tissue. Occasionally fat necrosis may mimic a breast cancer clinically, mammographically, and sonographically. There have been some previous reports on the MR imaging of the fat necrosis. In some MR findings of fat necrosis, it was difficult to distinguish it from malignant lesions. We report a case of fat necrosis presenting the irregular enhancement with the non-enhancing area of central areas on MRI.

MR imaging of the breast for the detection, diagnosis, and staging of breast cancer

With the introduction of contrast agents, advances in surface coil technology, and development of new imaging protocols, contrast agent-enhanced magnetic resonance (MR) imaging has emerged as a promising modality for detection, diagnosis, and staging of breast cancer. The reported sensitivity of MR imaging for the visualization of invasive cancer has approached 100%. There are many examples in the literature of MR imaging--demonstrated mammographically, sonographically, and clinically occult breast cancer. Often, breast cancer detected on MR images has resulted in a change in patient care. Despite these results, there are many unresolved issues, including no defined standard technique for contrast-enhanced breast MR imaging, no standard interpretation criteria for evaluating such studies, no consensus on what constitutes clinically important enhancement, and no clearly defined clinical indications for the use of MR imaging. Furthermore, this technology remains costly, and issues of cost-effectiveness and cost competition from percutaneous biopsy have yet to be fully addressed. These factors along with the lack of commercially available MR imaging--guided localization and biopsy systems have slowed the transfer of this imaging technology from research centers to clinical breast imaging practices. Technical requirements, potential clinical applications, and potential pitfalls and limitations of contrast-enhanced MR imaging as a method to help detect, diagnose, and stage breast cancer will be described.