Spectrum of the Breast Lesions With Increased 18F-FDG Uptake on PET/CT

Joint EANM-SNMMI guideline on the role of 2-[18F]FDG PET/CT in no special type breast cancer : (endorsed by the ACR, ESSO, ESTRO, EUSOBI/ESR, and EUSOMA)

INTRODUCTION

There is much literature about the role of 2-[18F]FDG PET/CT in patients with breast cancer (BC). However, there exists no international guideline with involvement of the nuclear medicine societies about this subject.

PURPOSE

To provide an organized, international, state-of-the-art, and multidisciplinary guideline, led by experts of two nuclear medicine societies (EANM and SNMMI) and representation of important societies in the field of BC (ACR, ESSO, ESTRO, EUSOBI/ESR, and EUSOMA).

METHODS

Literature review and expert discussion were performed with the aim of collecting updated information regarding the role of 2-[18F]FDG PET/CT in patients with no special type (NST) BC and summarizing its indications according to scientific evidence. Recommendations were scored according to the National Institute for Health and Care Excellence (NICE) criteria.

RESULTS

Quantitative PET features (SUV, MTV, TLG) are valuable prognostic parameters. In baseline staging, 2-[18F]FDG PET/CT plays a role from stage IIB through stage IV. When assessing response to therapy, 2-[18F]FDG PET/CT should be performed on certified scanners, and reported either according to PERCIST, EORTC PET, or EANM immunotherapy response criteria, as appropriate. 2-[18F]FDG PET/CT may be useful to assess early metabolic response, particularly in non-metastatic triple-negative and HER2+ tumours. 2-[18F]FDG PET/CT is useful to detect the site and extent of recurrence when conventional imaging methods are equivocal and when there is clinical and/or laboratorial suspicion of relapse. Recent developments are promising.

CONCLUSION

2-[18F]FDG PET/CT is extremely useful in BC management, as supported by extensive evidence of its utility compared to other imaging modalities in several clinical scenarios.

Unexpected focal fluorodeoxyglucose uptake in main organs; pass through or pass by?

Since the inception of fluorine-18 fluorodeoxyglucose (F-18 FDG), positron emission tomography/computed tomography (PET/CT) utilizing F-18 FDG has become widely accepted as a valuable imaging modality in the field of oncology, with global prevalence in clinical practice. Given that a single Torso PET/CT scan encompasses the anatomical region from the skull base to the upper thigh, the detection of incidental abnormal focal hypermetabolism in areas of limited clinical interest is both feasible and not uncommon. Numerous investigations have been undertaken to delineate the distinctive features of these findings, yet the outcomes have proven inconclusive. The incongruent results of these studies present a challenge for physicians, leaving them uncertain about the appropriate course of action. This article provides a succinct overview of the characteristics of fluorodeoxyglucose, followed by a comprehensive discussion of the imaging findings and clinical significance associated with incidental focal abnormal F-18 FDG activity in several representative organs. In conclusion, while the prevalence of unrecognized malignancy varies across organs, malignancies account for a substantial proportion, ranging from approximately one-third to over half, of incidental focal uptake. In light of these rates, physicians are urged to exercise vigilance in not disregarding unexpected uptake, facilitating more assured clinical decisions, and advocating for further active evaluation.

Breast cancer in a Hispanic patient with Werner syndrome

Werner Syndrome is a rare autosomal recessive condition characterized by premature aging and increased risk of malignancies due to gene mutations associated with DNA stability. We present the first case report of a 29-year-old Hispanic female with WS diagnosed with breast cancer. Diagnostic mammography and ultrasound, breast MRI and PET examinations revealed two lesions biopsy proven as invasive ductal carcinoma. The patient underwent neoadjuvant chemotherapy and radical mastectomy. Recurrence occurred 10 months postoperatively with molecular analysis demonstrating TP53 mutations. The multifactorial assessment of breast cancer in this case study is crucial towards optimizing screening, diagnosis and management of this disease in patients with WS.

Performance of dedicated breast PET in breast cancer screening: comparison with digital mammography plus digital breast tomosynthesis and ultrasound

OBJECTIVE

To compare the diagnostic performance of dedicated breast positron emission tomography (dbPET) in breast cancer screening with digital mammography plus digital breast tomosynthesis (DM-DBT) and breast ultrasound (US).

METHODS

Women who participated in opportunistic whole-body PET/computed tomography cancer screening programs with breast examinations using dbPET, DM-DBT, and US between 2016-2020, whose results were determined pathologically or by follow-up for at least 1 year, were included. DbPET, DM-DBT, and US assessments were classified into four diagnostic categories: A (no abnormality), B (mild abnormality), C (need for follow-up), and D (recommend further examination). Category D was defined as screening positive. Each modality's recall rate, sensitivity, specificity, and positive predictive value (PPV) were calculated per examination to evaluate their diagnostic performance for breast cancer.

RESULTS

Out of 2156 screenings, 18 breast cancer cases were diagnosed during the follow-up period (10 invasive cancers and eight ductal carcinomas in situ [DCIS]). The recall rates for dbPET, DM-DBT, and US were 17.8%, 19.2%, and 9.4%, respectively. The recall rate of dbPET was highest in the first year and subsequently decreased to 11.4%. dbPET, DM-DBT, and US had sensitivities of 72.2%, 88.9%, and 83.3%; specificities of 82.6%, 81.4%, and 91.2%; and PPVs of 3.4%, 3.9%, and 7.4%, respectively. The sensitivities of dbPET, DM-DBT, and US for invasive cancers were 90%, 100%, and 90%, respectively. There were no significant differences between the modalities. One case of dbPET-false-negative invasive cancer was identified in retrospect. DbPET had 50% sensitivity for DCIS, while that of both DM-DBT and US was 75%. Furthermore, the specificity of dbPET in the first year was the lowest among all periods, and modalities increased over the years to 88.7%. The specificity of dbPET was significantly higher than that of DM-DBT (p < 0.01) in the last 3 years.

CONCLUSIONS

DbPET had a compatible sensitivity to DM-DBT and breast US for invasive breast cancer. The specificity of dbPET was improved and became higher than that of DM-DBT. DbPET may be a feasible screening modality.

Prospective validation of 18F-Fluoroethylcholine as a tracer in PET/MRI for the evaluation of breast lesions and prediction of lymph node status

PURPOSE

To assess 18F-Fluoroethylcholine (18F-FEC) as a PET/MRI tracer in the evaluation of breast lesions, breast cancer aggressiveness, and prediction of lymph node status.

MATERIALS AND METHODS

This prospective, monocentric study was approved by the ethics committee and patients gave written, informed consent. This clinical trial was registered in the EudraCT database (Number 2017-003089-29). Women who presented with suspicious breast lesions were included. Histopathology was used as reference standard. Simultaneous 18F-FEC PET/MRI of the breast was performed in a prone position with a dedicated breast coil. MRI was performed using a standard protocol before and after contrast agent administration. A simultaneous read by nuclear medicine physicians and radiologists collected the imaging data of MRI-detected lesions, including the maximum standardized 18F-FEC-uptake value of breast lesions (SUV_maxT) and axillary lymph nodes (SUV_maxLN). Differences in SUV_max were evaluated with the Mann-Whitney U test. To calculate diagnostic performance, the area under the receiver operating characteristics curve (ROC) was used.

RESULTS

There were 101 patients (mean age 52.3 years, standard deviation 12.0) with 117 breast lesions included (30 benign, 7 ductal carcinomas in situ, 80 invasive carcinomas). 18F-FEC was well tolerated by all patients. The ROC to distinguish benign from malignant breast lesions was 0.846. SUV_maxT was higher if lesions were malignant (p < 0.001), had a higher proliferation rate (p = 0.011), and were HER2-positive (p = 0.041). SUV_maxLN was higher in metastatic lymph nodes, with an ROC of 0.761 for SUV_maxT and of 0.793 for SUV_maxLN. CONCLUSION: Simultaneous 18F-FEC PET/MRI is safe and has the potential to be used for the evaluation of breast cancer aggressiveness, and prediction of lymph node status.

Reproducibility assessment of uptake on dedicated breast PET for noise discrimination

OBJECTIVES

Dedicated breast PET (dbPET) systems have improved the detection of small breast cancers but have increased false-positive diagnoses due to an increased chance of noise detection. This study examined whether reproducibility assessment using paired images helped to improve noise discrimination and diagnostic performance in dbPET.

METHODS

This study included 21 patients with newly diagnosed breast cancer who underwent [¹⁸F]FDG-dbPET and contrast-enhanced breast MRI. A 10-min dbPET data scan was acquired per breast, and two sets of reconstructed images were generated (named dbPET-1 and dbPET-2, respectively), each of which consisted of randomly allocated 5-min data from the 10-min data. Uptake spots higher than the background were indexed for the study with visual assessment. All indexed uptakes on dbPET-1 were evaluated using dbPET-2 for reproducibility. MRI findings based on the Breast Imaging-Reporting and Data System (BI-RADS) 2013 were used as the gold standard. Uptake spots that corresponded to BI-RADS 1 on MRI were considered noise, while those with BI-RADS 4b-6 were considered malignancies. The diagnostic performance of dbPET for malignancy was evaluated using four different criteria: any uptake on dbPET-1 regarded as positive (criterion A), a subjective visual assessment of dbPET-1 (criterion B), reproducibility assessment between dbPET-1 and dbPET-2 (criterion C), and a combination of B and C (criterion D).

RESULTS

A total of 213 indexed uptake spots were identified on dbPET-1, including 152, 15, 6, 6, and 34 lesions classified as BI-RADS MRI categories 1, 2, 4b, 4c, and 5, respectively. Overall, 31.9% of the index uptake values were reproducible. All malignant lesions were reproducible, whereas 93.4% of noise was not reproducible. The sensitivities for malignancy for criteria A, B, C, and D were 100%, 91.3%, 100%, and 91.3%, respectively, with positive predictive values (PPVs) of 21.4%, 68.9%, 67.6%, and 82.4%, respectively.

CONCLUSIONS

Our results demonstrated that reproducibility assessment helped reduce false-positive findings caused by noise on dbPET without lowering the sensitivity for malignancy. While subjective visual assessment was also efficient in increasing PPV, it occasionally missed malignant uptake.

Modern Imaging Techniques in the Study and Disease Diagnosis of the Mammary Glands of Animals

The study of the structure and function of the animals' mammary glands is of key importance, as it reveals pathological processes at their onset, thus contributing to their immediate treatment. The most frequently studied mammary diseases are mastitis in cows and ewes and mammary tumours in dogs and cats. Various imaging techniques such as computed tomography, positron emission tomography, magnetic resonance imaging, and ultrasonographic techniques (Doppler, contrast-enchanced, three-dimensional and elastography) are available and can be applied in research or clinical practice in order to evaluate possible abnormalities in mammary glands, as well as to assist in the differential diagnosis. In this review, the above imaging technologies are described, and the perspectives of each method are highlighted. It is inferred that ultrasonographic modalities are the most frequently used imaging techniques for the diagnosis of clinical or subclinical mastitis and treatment guidance on a farm. In companion animals, a combination of imaging techniques should be applied for a more accurate diagnosis of mammary tumours. In any case, the confirmation of the diagnosis is provided by laboratory techniques.

Intraductal Papilloma With Carcinoma of the Breast Described by Dedicated Breast 18F-FDG PET

ABSTRACT

Intraductal papilloma (IDP) is a benign tumor of the breast. However, IDP has been reported to show high uptake of 18F-FDG using whole-body PET. We experienced IDP with low-grade ductal carcinoma in situ using dedicated breast PET, which is more sensitive than whole-body PET. The 18F-FDG uptake of the whole tumor was high, and differentiation between the carcinoma and the residual benign lesion was difficult. This is the first report of IDP detected with dedicated breast PET. Diagnosis of IDP is sometimes controversial; papilloma may show glucose uptake similar to that of low-grade carcinoma.

PET-CT in Clinical Adult Oncology: II. Primary Thoracic and Breast Malignancies

Simple Summary

Positron emission tomography (PET), typically combined with computed tomography (CT), has become a critical advanced imaging technique in oncology. With PET-CT, a radioactive molecule (radiotracer) is injected in the bloodstream and localizes to sites of tumor because of specific cellular features of the tumor that accumulate the targeting radiotracer. The CT scan, performed at the same time, provides information to facilitate assessment of the amount of radioactivity from deep or dense structures, and to provide detailed anatomic information. PET-CT has a variety of applications in oncology, including staging, therapeutic response assessment, restaging, and surveillance. This series of six review articles provides an overview of the value, applications, and imaging and interpretive strategies of PET-CT in the more common adult malignancies. The second article in this series addresses the use of PET-CT in breast cancer and other primary thoracic malignancies.

Abstract

Positron emission tomography combined with x-ray computed tomography (PET-CT) is an advanced imaging modality with oncologic applications that include staging, therapy assessment, restaging, and surveillance. This six-part series of review articles provides practical information to providers and imaging professionals regarding the best use of PET-CT for the more common adult malignancies. The second article of this series addresses primary thoracic malignancy and breast cancer. For primary thoracic malignancy, the focus will be on lung cancer, malignant pleural mesothelioma, thymoma, and thymic carcinoma, with an emphasis on the use of FDG PET-CT. For breast cancer, the various histologic subtypes will be addressed, and will include ¹⁸F fluorodeoxyglucose (FDG), recently Food and Drug Administration (FDA)-approved ¹⁸F-fluoroestradiol (FES), and ¹⁸F sodium fluoride (NaF). The pitfalls and nuances of PET-CT in breast and primary thoracic malignancies and the imaging features that distinguish between subcategories of these tumors are addressed. This review will serve as a resource for the appropriate roles and limitations of PET-CT in the clinical management of patients with breast and primary thoracic malignancies for healthcare professionals caring for adult patients with these cancers. It also serves as a practical guide for imaging providers, including radiologists, nuclear medicine physicians, and their trainees.

Multimodality imaging of breast hematomas and their mimickers

While breast hematomas are common, their imaging features are often underrecognized or mistaken for other conditions.Diagnosis of acute hematomas is generally easy when associated with a recent history of breast trauma, surgery, or percutaneous biopsy. However, minor trauma might not always be remembered, and breast hematoma might have longlasting imaging manifestations when associated with fat necrosis. Also, because of the increasing use of breast MRI and FDG-PET/CT, breast hematomas are increasingly detected as incidentalomas and may mimic malignancies.Conversely, breast hematomas may also be associated with authentic malignant processes.In this pictorial review, we present the natural history of breast hematomas, their various imaging features, as well as their differential diagnoses, highlighting the situations requiring histopathological correlation.

FDG PET/CT of Primary Breast Lymphoma in a Man

ABSTRACT

Primary lymphoma of the male breast is extremely rare. We describe FDG PET/CT findings in a man with primary breast lymphoma in his right breast. The breast tumor showed intense FDG uptake mimicking breast carcinoma.

18F-FDG PET/CT in a Patient With Matrix-Producing Carcinoma of the Breast

ABSTRACT

A 47-year-old woman presented with a large mass in the upper inner quadrant of the left breast. 18F-FDG PET/CT revealed a low-density left breast mass with heterogeneous ring-like 18F-FDG uptake. Core needle biopsy of the tumor revealed a rare subtype of metaplastic breast carcinoma, matrix-producing carcinoma. The tumor size slightly decreased after 6 cycles of neoadjuvant chemotherapy with docetaxel and epirubicin. The left breast was entirely resected subsequently, and the matrix-producing carcinoma of the breast was ultimately diagnosed.

Interference of Known or Suspected Endometriosis in Reporting FDG PET/CT Performed in Another Indication

INTRODUCTION

Endometriosis is a common gynecologic condition that may be visualized on 18F-FDG PET/CT and mimic lesions of malignancy. We analyzed the interference of known or suspected endometriosis in reporting 18F-FDG PET/CT performed in another indication.

RESULTS

The PET/CT images of 18 women with known (n = 15) or suspected (n = 3) endometriosis were analyzed. Based on clinical follow-up and results of other imaging, biopsy, and/or postsurgical histology, the presence of lesions of endometriosis at the time of 18F-FDG PET/CT was confirmed in 13 of 18 patients (72%). The per-patient positivity rate of 18F-FDG PET/CT was 8/18 (44%; 95% confidence interval, 22%-69%). The patient-based detection rate of 18F-FDG PET/CT in patients with confirmed lesions of endometriosis was 8/13 (62%; confidence interval, 32%-86%). On per-lesion/site basis, 18F-FDG PET/CT detected 11 of 20 sites (55%) of endometriosis. The SUVmax of these lesions/sites ranged between 1.8 and 5.3 (median, 3.8). In 9 of 18 patients (50%), a total of 13 non-endometriosis-related lesions/sites were detected by 18F-FDG PET/CT; their SUVmax ranged between 2.7 and 23 (median, 9.4).

CONCLUSION

The interference of known or suspected endometriosis in reporting 18F-FDG PET/CT performed in another indication was limited but possible and should be kept in mind, even in postmenopausal women, as the oldest patient with 18F-FDG-positive endometriosis was aged 63 years. The lesions of endometriosis showed inconstant 18F-FDG uptake with overlap of SUVmax with low-grade malignancies. In our series, the greatest SUVmax value of lesion of endometriosis was 5.3, somewhat higher than the threshold of 4 previously proposed for identification of malignant transformation of endometriosis.

Micropapillary Breast Carcinoma: From Molecular Pathogenesis to Prognosis

Invasive micropapillary carcinoma (IMPC) of the breast is an infrequent type of breast cancer often discussed for its potency for lymphovascular invasion and difficulty in accurate imaging estimation. Micropapillary carcinomas are noted to be present as larger tumors, of higher histological grade and a notably higher percentage of disease-positive lymph nodes. Hormonal and HER-2 positivity in IMPC is also commoner when compared to other NST carcinomas. IMPC occurs either as a pure form or more often as a component of mixed Non-Specific Type (NST) carcinoma. The latest data suggest that despite having comparable survival rates to other histological subtypes of breast carcinoma, effective surgical treatment often requires extended surgical margins and vigilant preoperative axillary staging due to an increased incidence of lymph node invasion, and locoregional recurrence. Moreover, the presence of micropapillary in situ components within tumors also seems to alter tumor aggression and influence the nodal disease stage. In this review, we present an overview of the current literature of micropapillary carcinoma of the breast from biology to prognosis, focusing on biological differences and treatment.

FDG-Avid Sclerosing Adenosis of the Breast Mimicking Malignancy

ABSTRACT

Sclerosing adenosis is a common benign proliferative disorder of the breast. We describe FDG PET/CT findings in a case of sclerosing adenosis showing focal intense FDG uptake mimicking malignancy. This case indicates that sclerosing adenosis should be included in the differential diagnosis of focal breast FDG accumulation along with malignant and nonmalignant conditions.

11C-Methionine Uptake in the Lactating Human Breast

ABSTRACT

A 33-year-old nursing mother who underwent resection of a glioblastoma of the right hemisphere was referred for a 11C-methionine PET/MR scan to exclude cancer recurrence. In whole-body PET imaging, a slight radiotracer uptake could be observed in the mammary glands, reflecting lactation status. In this case report, we initially describe 11C-methionine uptake in the human breast and discuss any consequences arising from this special situation.

Non-conventional and Investigational PET Radiotracers for Breast Cancer: A Systematic Review

Breast cancer is one of the most common malignancies in women, with high morbidity and mortality rates. In breast cancer, the use of novel radiopharmaceuticals in nuclear medicine can improve the accuracy of diagnosis and staging, refine surveillance strategies and accuracy in choosing personalized treatment approaches, including radioligand therapy. Nuclear medicine thus shows great promise for improving the quality of life of breast cancer patients by allowing non-invasive assessment of the diverse and complex biological processes underlying the development of breast cancer and its evolution under therapy. This review aims to describe molecular probes currently in clinical use as well as those under investigation holding great promise for personalized medicine and precision oncology in breast cancer.

The Challenge of Staging Breast Cancer With PET/CT in the Era of COVID Vaccination

ABSTRACT

We report a case series of biopsy-proven reactive axillary lymph nodes, which were avid on FDG PET/CT in breast cancer patients post COVID-19 vaccination. With 4 cases presenting in a consecutive 10-day period, it became apparent that metabolically active axillary lymphadenopathy is an adverse effect of COVID-19 vaccines, currently being deployed worldwide. This may lead to patients undergoing unnecessary biopsy. We have started taking a COVID-19 vaccine status history before PET/CT. If enlarged/metabolically active axillary nodes are identified in the ipsilateral vaccinated arm, then axillary ultrasound at 4 weeks is suggested.

Primary breast lymphoma of childhood: a case report and review of literature

Background

Primary breast lymphoma (PBL) is an extremely rare neoplasm in children; by definition, it manifests in the breast without evidence of lymphoma elsewhere, except ipsilateral axillary nodes.

Case presentation

We report a case of a 15-year-old girl diagnosed with diffuse large B-cell lymphoma (DLBCL) of the right breast: the patient received chemotherapy and rituximab, achieving complete remission. A literature review revealed other 11 cases of pediatric PBL; it mainly affects female adolescents and can involve right and left breast equally. Different histologic subtypes have been described, arising from both B-cell and T-cell. Therapeutic approaches were very different, from chemotherapy to local treatment with surgery and/or radiotherapy.

Conclusions

Our case is the first in which rituximab was administered, suggesting to be a promising therapy in B-cell PBL, as already demonstrated in pediatric B-cell lymphoma from other sites. Further investigations are needed to identify prognostic factors and establish the most effective treatment.

Clustering subtypes of breast cancer by combining immunohistochemistry profiles and metabolism characteristics measured using FDG PET/CT

BACKGROUND

The aim of this study was to investigate the effect of combining immunohistochemical profiles and metabolic information to characterize breast cancer subtypes.

METHODS

This retrospective study included 289 breast tumors from 284 patients who underwent preoperative 18 F-fluorodeoxyglucose (FDG) positron emission tomography/ computed tomography (PET/CT). Molecular subtypes of breast cancer were classified as Hormonal, HER2, Dual (a combination of both Hormonal and HER2 features), and triple-negative (TN). Histopathologic findings and immunohistochemical results for Ki-67, EGFR, CK 5/6, and p53 were also analyzed. The maximum standardized uptake value (SUV) measured from FDG PET/CT was used to evaluate tumoral glucose metabolism.

RESULTS

Overall, 182, 24, 47, and 36 tumors were classified as Hormonal, HER2, Dual, and TN subtypes, respectively. Molecular profiles of tumor aggressiveness and the tumor SUV revealed a gradual increase from the Hormonal to the TN type. The tumor SUV was significantly correlated with tumor size, expression levels of p53, Ki-67, and EGFR, and nuclear grade (all p < 0.001). In contrast, the tumor SUV was negatively correlated with the expression of estrogen receptors (r = - 0.234, p < 0.001) and progesterone receptors (r = - 0.220, p < 0.001). Multiple linear regression analysis revealed that histopathologic markers explained tumor glucose metabolism (adjusted R-squared value 0.238, p < 0.001). Tumor metabolism can thus help define breast cancer subtypes with aggressive/adverse prognostic features.

CONCLUSIONS

Metabolic activity measured using FDG PET/CT was significantly correlated with the molecular alteration profiles of breast cancer assessed using immunohistochemical analysis. Combining molecular markers and metabolic information may aid in the recognition and understanding of tumor aggressiveness in breast cancer and be helpful as a prognostic marker.

PET/CT Variants and Pitfalls in Breast Cancers

There are a number of normal variants and pitfalls which are important to consider when evaluating F-18 Fluorodeoxyglucose (FDG) with Positron Emission Tomography (PET) in breast cancer patients. Although FDG-PET is not indicated for the initial diagnosis of breast cancer, focally increased glucose metabolism within breast tissue represents a high likelihood for a neoplastic process and requires further evaluation. Focally increased glucose metabolism is not unique to breast cancer. Other malignancies such as lymphoma, metastases from solid tumors as well as inflammatory changes also may demonstrate increased glucose metabolism either within the breast or at other sites throughout the body. Importantly, benign breast disease may also exhibit increased glucose metabolism, limiting the specificity of FDG-PET. Breast cancer has a wide range of metabolic activity attributed to tumor heterogeneity and breast cancer subtype. Intracellular signaling pathways regulating tumor glucose utilization contribute to these pitfalls of PET/CT in breast cancer. The evaluation of axillary lymph nodes by FDG-PET is less accurate than sentinel lymph node procedure, however is very accurate in identifying level II and III axillary lymph node metastases or retropectoral metastases. It is important to note that non-malignant inflammation in lymph nodes are often detected by modern PET/CT technology. Therefore, particular consideration should be given to recent vaccinations, particularly to COVID-19, which can commonly result in increased metabolic activity of axillary nodes. Whole body FDG-PET for staging of breast cancer requires specific attention to physiologic variants of FDG distribution and a careful comparison with co-registered anatomical imaging. The most important pitfalls are related to inflammatory changes including sarcoidosis, sarcoid like reactions, and other granulomatous diseases as well as secondary neoplastic processes.

Bilateral Silicone Granulomas Mimicking Breast Cancer Recurrence on 18F-FDG PET/CT

ABSTRACT

We report the case of a 45-year-old woman with a history of right breast reconstruction with silicone implant for breast cancer. An 18F-FDG PET/CT performed several years later revealed the presence of 18F-FDG-avid nodules at the periphery of the silicone implant, in the right internal mammary chain, and in the contralateral breast. Needle core biopsies were positive for bilateral silicone granulomas, without any sign of malignancy. This case displays intense 18F-FDG uptake in silicone granulomas affecting the contralateral breast after implant reconstruction.

False-Positive 18F-FDG PET/CT Uptake in Unilateral Lactation

A 31-year-old woman (7 months postpartum and lactating) with multiple sclerotic bone lesions was referred for an ¹⁸F-FDG PET/CT scan for characterization. The scan demonstrated unilateral diffuse intense FDG uptake corresponding to dense soft tissue in the right breast, likely related to secretory hyperplasia. On further questioning, it was made apparent that she had only been breastfeeding from the right breast. While the left breast also demonstrated dense soft tissue to a lesser degree, no significant FDG uptake was seen. The sclerotic bone lesions were not FDG avid, likely due to a separate non-FDG avid benign condition or bony metastases from a non-FDG avid primary malignancy. This was reinforced by the fact that subsequent investigations including serial bilateral breast ultrasound and percutaneous biopsy demonstrated no definite evidence of malignancy in the bilateral breasts. The histopathology findings of an open surgical biopsy of sclerotic lesions in the left posterior ilium were also nonspecific, favouring bone dysplasia with no evidence of malignancy.

18F-FDG PET/CT in the Evaluation of Solitary Extramedullary Plasmacytoma: A Case Series

The role of fluorine-18-fluorodeoxyglucose positron emission tomography/ computed tomography (¹⁸F-FDG PET/CT) in patients with multiple myeloma (MM) and other plasma cell disorders is well-known. Solitary plasmacytoma (SP), an extremely rare form within this entity accounting for approximately 4% of plasma cell malignancies, can be classified as solitary bone plasmacytoma (SBP) or solitary extramedullary plasmacytoma (SEMP). Extramedullary plasmacytoma (EMP) is a rare neoplasm characterized by the monoclonal proliferation of plasma cells outside the bone marrow. Breast and craniocerebral regions are the uncommon sites of the presentations of EMP, rarely reported in the literature. The most frequent site of presentation is the upper airways. The EMPs have similar pathogenesis as MM; however, they differ in management as they are radiosensitive in nature, and radiotherapy is the preferred treatment modality. As SEMP has a better prognosis than SPB with a lower conversion rate to MM, accurate staging is essential to plan for the treatment. The ¹⁸F-FDG PET/CT has higher sensitivity for the evaluation of treatment response. In the present case series, it was aimed to depict the role of ¹⁸F-FDG PET/CT in newly diagnosed SEMP with different sites of origin to exclude further lesions leading to changes in the treatment plan and treatment response assessment.

The frequency and malignancy rate of incidental focal breast lesions identified by 18F-fluorodeoxyglucose positron emission tomography

OBJECTIVE

To evaluate the frequency and malignancy rate of incidental focal uptake of 18F-fluorodeoxyglucose (FDG) in the breast on PET/computed tomography (CT).

MATERIAL AND METHODS

All PET/CT scan reports from a single institution from 2010 to 2017 were electronically searched for words or phrases related to FDG uptake in the breast. Potentially eligible PET/CT scans were manually reviewed for the presence of focal incidental findings in the breast, and a final diagnosis was established based on pathology, clinical examinations, and clinical follow-up.

RESULTS

A total of 19 551 PET/CT scans were reviewed, from which 66 patients (0.3%) presented with unexpected focal FDG-avid lesions of the breast. Fifty-three patients (80.3%) had follow-up evaluations. The final diagnosis showed malignancies in 38 patients. Thirty-four patients had biopsy-verified cancer (primary breast cancers, n = 30; metastasis, n = 4), and four patients with known lymphoma showed a tumour response in the breast after chemotherapy. The malignancy rate was 85.0% among patients who underwent biopsy (34 of 40 patients). The SUVmax was significantly higher in patients with a final malignant diagnosis (n = 38) than in those with a benign diagnosis (n = 15) (4.5 ± 2.9 vs. 2.7 ± 1.3, P = 0.03).

CONCLUSION

Incidental uptake of FDG in the breast was rare. However, the malignancy rate was high among these patients, particularly among patients who had a follow-up biopsy. We recommend biopsy or thorough follow-up in patients with incidental focal uptake of FDG in the breast.

Metabolic changes in breast cancer on dual-time-point 18F-FDG PET/CT imaging according to primary tumor uptake and background parenchymal enhancement

OBJECTIVE

This study was aimed at investigating metabolic changes in breast cancer on dual-time-point ¹⁸F-FDG PET/CT imaging (DTPI) according to primary tumor uptake and determining whether this technique is affected by background parenchymal enhancement (BPE).

METHODS

A total of 189 patients with newly diagnosed breast cancer who underwent DTPI examination were retrospectively evaluated. DTPI was performed using a standard FDG/PET protocol followed by delayed image acquisition at 120 min after injection. Patients were divided into two groups according to primary tumor uptake as breast cancer with low maximum standard uptake value (SUVmax) (< 2.5) and high SUVmax (≥ 2.5). The maximal SUV of the primary breast tumor (T-SUVmax), contralateral breast parenchyma uptake (B-SUVmax) according to different BPE grades, tumor to background ratio (T/B-SUVmax), and their percentage changes between early and delayed images (retention index, RI) were calculated.

RESULTS

For primary tumor uptake, tumors with high SUV had a significant increase in mean T-SUVmax between early and delayed images (8.17 vs. 9.16, P < 0.001), and %RI T-SUVmax was 10.52%. Conversely, mean T-SUVmax did not change between early and delayed images for tumors with low SUV (1.96 vs. 1.94, P = 0.610), and %RI T-SUVmax was - 1.41%. The mean %RI B-SUVmax was - 12.43% for minimal BPE, - 14.19% for mild BPE, - 19.49% for moderate BPE, and - 21.25% for marked BPE grade, indicating that higher BPE grades undergo better washouts on delayed imaging (β = - 3.220, P < 0.001 for trend). The %RI T/B-SUVmax of both breast cancer groups with low SUV and high SUV was 18.86% and 32.47%, respectively.

CONCLUSIONS

Breast cancer with low SUV undergoes no significant change in SUV on DTPI; however, washing of background parenchymal activity was evident over time, resulting in significantly increased tumor contrast in delayed images, which leads to increased sensitivity. Breast parenchymal washout was more significant with increased BPE level. Therefore, DTPI is expected to be more useful for evaluating breast lesions in regions with marked BPE on MRI.

Clinical and imaging features of idiopathic granulomatous mastitis - The diagnostic challenges and a brief review

Idiopathic granulomatous mastitis (IGM), or granulomatous lobular mastitis is a rare, benign, inflammatory condition of the breast, without an identifiable underlying etiology. The clinical and imaging diagnosis of this entity is challenging with the presentation frequently mimicking inflammatory breast carcinoma (IBC). Mammography and breast ultrasound (US) have an important role in its detection, however, biopsy is imperative for histopathological confirmation. We present three cases of biopsy proven IGM, highlighting the variability of the clinical and imaging features,brieflyreview the relevant literature and discuss the challenges associated with its diagnosis and management.

Post Contusion Breast Hematoma Mimicking Malignancy on FDG PET/CT

A 32-year-old woman was treated for breast carcinoma. Posttreatment FDG PET/CT scan revealed complete response, but in the contralateral breast, unexpected incidental intense FDG uptake was seen with a differential diagnosis of both malignant and benign causes. Medical history revealed recent breast contusion. The lesion was further evaluated by mammogram and ultrasound, which were compatible with deep breast bruise. Histopathology showed no malignancy. Subsequent FDG PET/CT study showed breast uptake normalization. This case shows that postcontusion breast hematoma can cause a potential pitfall mimicking breast malignancy on FDG PET/CT.

Management of Incidental Breast Lesions Detected at Nuclear Medicine Examinations

Nuclear medicine studies are often performed in patients with breast cancer; however, incidental radiotracer uptake in the breasts can be observed in patients with nonbreast malignancies. Benign and malignant lesions can be identified on planar, SPECT, and PET scans. This review will outline the molecular and radiographic imaging appearance of benign and malignant breast lesions on sestamibi scans, bone scans, radioiodine studies, as well as PET studies using fluorine 18 (¹⁸F) fluorodeoxyglucose, gallium 68 (⁶⁸Ga) tetraazacyclododecane tetraacetic acid octreotate (or DOTATATE), ⁶⁸Ga prostate-specific membrane antigen, and ¹⁸F-fluciclovine radiotracers. Recognizing these lesions at molecular and anatomic imaging is important to ensure accurate diagnosis and appropriate management. Keywords: Breast, Mammography, Molecular Imaging, PET/CT, Radionuclide Studies, SPECT/CT © RSNA, 2020.

Is there a difference in FDG PET findings of invasive ductal carcinoma of the breast with and without coexisting DCIS?

OBJECTIVES

Studies have reported that invasive ductal carcinoma (IDC) with coexisting ductal carcinoma in situ (DCIS) show lower metastatic potential and recurrence and better overall survival than pure IDC. In this study, we assessed F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) images of patients with newly diagnosed IDC to determine if there is any difference in PET findings in IDC-DCIS and pure IDC cases.

METHODS

FDG PET/CT images of patients with newly diagnosed IDC of the breast who subsequently underwent breast surgery and had histopathology result in our records were further evaluated. Tumor grade, pathological staging, and presence of DCIS were noted from the histopathology results. Standardized uptake value (SUV) of the primary tumor (SUVmax and SULmax), other hypermetabolic foci in the breast, and ipsilateral normal breast were measured. Presence of axillary and distant metastases was noted.

RESULTS

Fifty seven (57) patients with IDC were included. Coexisting DCIS was present in 44 (IDC-DCIS) and not present in 13 (pure IDC) cases. Per histopathology, the primary tumor was unifocal in 33 IDC-DCIS (75%) and 12 pure IDC (92.3%) cases, and multifocal in 11 IDC-DCIS cases (25%), and 1 pure IDC case (7.7%). FDG uptake was multifocal in 20 IDC-DCIS cases (45.5%) and 1 pure IDC case (7.7%), and unifocal in 24 IDC-DCIS (54.5%), and 12 pure IDC (92.3%) cases. There was no significant difference in patient age, size of the primary tumor, SUVmax and SULmax of the primary tumor and SUVmax of the normal breast in IDC-DCIS and pure IDC cases (p>0.05). Pathology showed axillary metastasis in all 13 pure IDC (100%), and 27 IDC-DCIS (61.4%) cases. PET showed axillary uptake in 25 IDC-DCIS (56.8%), and 8 pure IDC (61.5%) cases, and abnormal/questionable distant uptake in 12 IDC-DCIS cases and 1 pure IDC case.

CONCLUSION

In our preliminary findings, multifocal breast FDG uptake and multifocal tumor appear to be more common in IDC-DCIS than pure IDC. There is no significant difference in SUV and size of the primary tumor in IDC-DCIS and pure IDC cases. Axillary metastases appear to be more common in pure IDC than IDC-DCIS cases.

A Comparison of Angiogenesis and Glycolytic Imaging in Patients With Clinical Suspected Locally Advanced Breast Cancer

F-FDG PET/CT imaging is an important diagnostic tool for accurate staging and assessment of response to neoadjuvant chemotherapy (NACT) in patients with locally advanced breast carcinoma (LABC). However, F-FDG being non-specific marker, it also accumulates in inflammatory conditions, leading to false positive results. Angiogenesis, an essential characteristic for tumor development, intrusion and metastasis can be imaged using Ga-labeled RGD tripeptide. We here depict a series of clinically staged LABC patients who underwent both Ga-DOTA-RGD2 and F-FDG PET/CT imaging for staging and illustrate the similarities and significant differences between the two tracers.

Prevalence of focal incidental breast uptake on FDG-PET/CT and risk of malignancy: a systematic review and meta-analysis

Background

FDG-PET/CT is increasingly used for oncologic and inflammatory diseases. Focal incidental FDG uptake occurs rarely in breast tissue but has often significant consequences. This study aimed to systematically review literature regarding focal incidental breast uptake (FIBU) on FDG-PET/CT in order to yield an update on the prevalence and risk of malignancy for FIBU.

Methods

A systematic search for relevant articles published between 2012 and 2018 was performed through MEDLINE, Embase, and Cochrane databases. Studies addressing the detection of FIBU in patients without a previous history of breast malignancy were included. The QUADAS-2 was used for quality assessment, and eligible data were pooled using a fixed-effects model. I² was calculated for the heterogeneity between studies.

Results

Eight studies containing 180,002 scans were included in the systematic review. The median prevalence of FIBU for both genders was 0.52% (range 0.18–22.5%). Prevalence for women was mentioned separately in five studies and varied from 0.51 to 23.5%. One study reporting a high prevalence was based on patients being staged for known malignancy, and the word “breast” was used in the search, which may have caused selection bias. Data from four studies were eligible for meta-analysis. A high degree of heterogeneity was observed for prevalence data (I² of 97.5%), while moderate heterogeneity was observed for data on malignancy risk assessment (I² of 62.8%). The pooled prevalence of FIBU in women was 0.61% (range 0.56–0.66%), and the pooled prevalence of malignancy of FIBUs was 38.7% (range 34.4–43.0%). The most commonly detected malignancy was invasive ductal carcinoma.

Conclusion

FIBU occurs rarely on FDG-PET/CT for female patients but yields a high risk of malignancy according to the results of published papers. Therefore, it should be considered relevant to further elucidate patients with incidentally detected FDG uptake in breast in clinical practice.

Electronic supplementary material

The online version of this article (10.1186/s41824-019-0063-5) contains supplementary material, which is available to authorized users.

Galactocele, Pitfall for the Evaluation by 18F-FDG PET/CT

A high F-FDG uptake was found in mammary lesions in a 36-year-old woman who underwent a PET/CT scan for initial staging of diffuse large B-cell lymphoma. The patient has given birth 2 months ago and was breastfeeding. Ultrasound-guided fine-needle aspiration of 1 lesion yielded creamy liquid consistent with milk and confirmed the diagnosis of galactocele.

Solitary Breast Metastasis From Rhabdomyosarcoma Shown on FDG PET/CT

Rhabdomyosarcoma rarely metastasizes to breast. A 15-year-old adolescent girl underwent FDG PET/CT scan for staging a newly diagnosed alveolar rhabdomyosarcoma. The images showed not only the abnormal activity in the region of the right maxillary sinus, consistent with the known primary tumor, but also an intense focal activity in the right breast. The right breast lesion was excised, and the pathological results showed alveolar rhabdomyosarcoma.

Burkitt lymphoma and cavernous sinus syndrome with breast uptake on 18F-FDG-PET/CT: A case report

RATIONALE

Burkitt lymphoma (BL) is a type of non-Hodgkin lymphoma that arises in the B-cells. Cavernous sinus involvement is rare, especially in adults. Here we report an unusual case of a 30-year-old HIV-positive woman with BL and cavernous sinus syndrome who also had intense bilateral breast uptake, related to menstrual cycle. Fluorine-18 2-fluoro-2-deoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) has been found to be useful in the management of BL.

PATIENT CONCERNS

A 30-year old female patient presented with a history of diplopia and headache.

DIAGNOSES

Magnetic resonance imaging revealed a large cavernous sinus mass. A bone marrow biopsy was done and demonstrated extensive marrow infiltration by Burkitt lymphoma. Further investigation detected the Epstein-Barr virus in her cerebrospinal fluid using qualitative polymerase chain reaction. 18F-FDG PET/CT imaging done revealed a hypermetabolic cavernous sinus mass, conglomerates of enlarged pelvic and para-aortic lymph nodes as well as diffuse bone marrow uptake. Intense bilateral breast uptake was noted coinciding with the start of menses.

INTERVENTIONS

She was started on chemotherapy with adjuvant radiotherapy.

OUTCOMES

After her first cycle of chemotherapy, repeat 18F-FDG PET/CT imaging revealed a marked reduction in the metabolic activity and size of the cavernous sinus mass and conglomerates of lymph nodes. The bone marrow activity was still visualized but less intense compared to the staging PET/CT.

LESSONS

A cavernous sinus mass will rarely be the primary lesion in Burkitt's Lymphoma. Our case demonstrates the role of 18F-FDG PET/CT in the assessment of such cases to detect other primary areas of disease involvement. It is useful in accurate initial staging and monitoring of treatment response in patients with Burkitt's Lymphoma.

Increased F-FDG Uptake in Bilateral Gynecomastia Secondary to Feminizing Adrenal Tumor: A Rare Case Report and Review of Literature

A 21 year old male who presented with painful enlargement of both the breasts and a hyperestrogenic state, was found to harbor a heterogeneous mass arising from the right adrenal on contrast enhanced Computed Tomography abdomen. The mass was hypermetabolic with no regional, nodal or distant metastases on Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography /Computed Tomography examination. Notably, substantial tracer uptake was seen in bilateral gynecomastia. The patient underwent a right adrenalectomy with the histopathology report confirming adrenocortical carcinoma. This case demonstrates utility of FDG PET/CT in adrenocortical carcinoma. However, when interpreting FDG PET/CT as a staging tool in oncological male patients, one should consider gynecomastia as a possible cause for increased FDG uptake in the breast as it may lead to a false positive interpretation.

Breast Fibroadenoma With Increased Activity on 68Ga DOTATATE PET/CT

Fibroadenoma is the most common benign breast tumor in women of reproductive age, carrying little to no risk of breast cancer development. We report on a case of a woman with history of neuroendocrine tumor who on follow-up imaging tests underwent whole-body PET/CT study using Ga DOTATATE. The scan showed increased focal activity in the right breast, which was biopsied revealing a fibroadenoma. The presented data suggests cell surface overexpression of somatostatin receptors by this benign breast tumor. Moreover, this finding emphasizes the need for cautious interpretation of Ga DOTATATE-avid breast lesions that could mimic malignancy in neuroendocrine tumor patients.