Invasive Lobular Carcinoma of the Breast With Solid Renal Metastasis on 18F-FDG PET/CT

Herein we present a case with recurrent invasive lobular carcinoma of the breast with solid renal metastasis detected on 18F-FDG PET/CT. Invasive lobular carcinoma constitutes ∼5%-15% of all invasive breast cancers and is the second most common type of breast cancer. 18F-FDG PET/CT is routinely used for staging and restaging invasive lobular carcinoma of the breast. Although distant solid organ metastasis is common, renal metastasis remains an exceptionally rare occurrence in ILC. This case highlights the importance of considering renal involvement in the metastatic spread of invasive lobular carcinoma, especially when using 18F-FDG PET/CT.

General characteristics of orbital metastasis in breast cancer: a narrative review of case reports

Breast-cancer metastasis has seen an increased incidence in recent years, owing to advancements in surveillance, diagnostic imaging, histopathological assessment, and treatment modalities. Metastasis to various sites, including the bone, lung, liver, and brain, is common in cancer patients. Orbital metastasis (OM) from breast cancer can lead to a range of symptoms, such as pain, palpebral ptosis, diplopia, ocular pain, vision loss, and a recessed eyeball. To explore the topic of systemic malignancies metastasizing to the orbit, a search was conducted on the PubMed service using keywords such as "orbit," "orbital," "cancer," "malignancy," and "metastasis." This review article aims to summarize the findings from the identified literature. Overall, 103 patients with breast cancer from 77 articles were investigated. The patients' mean age ± standard deviation was 58.73 ± 11.86 years. Types of breast pathology observed in the evaluated patients included lobular (32.1%), ductal pathology (35.9%), and unspecified (32%). The most common symptom was vision change 37.9% and diplopia 26.2%. Despite the rarity of OM in breast cancer, it is crucial to consider this condition due to its potential to exacerbate the functional status of the neoplastic disease. The primary treatment approach for orbital metastasis involves radiation therapy, often combined with systemic chemotherapy, hormone therapy or targeted therapy. These interventions aim to minimize symptoms and control disease progression. It is encouraging that advancements in medication, along with timely diagnosis and treatment, have the potential to improve outcomes for patients with orbital metastasis. However, further research is necessary to comprehensively evaluate all aspects of breast cancer metastasis to rare organs. A deeper understanding of the underlying mechanisms and identification of potential therapeutic targets could enhance treatment strategies and ultimately improve patient prognosis.

Enhancing precision in bone metastasis diagnosis for lobular breast cancer: reassessing the role of 18 F-FDG PET/CT

PURPOSE

Detection of osseous metastases by imaging can be challenging in patients with invasive lobular breast cancer (ILC). ILC may demonstrate low metabolic rate due to lower tumor cell density, decreased proliferation rate, diffuse infiltration of surrounding tissue, and low level of GLUT-1 expression. The aim of this study is to assess the diagnostic accuracy of 18 F-FDG PET/CT in identifying bone metastases in ILC patients.

MATERIAL AND METHODS

Out of 52 individuals diagnosed with lobular breast cancer and underwent 18 F-FDG PET/CT for evaluation of metastases, 21 patients were included in our study population after applying inclusion and exclusion criteria. The radiological and clinical follow-up of at least 6 months served as the reference standard comparator.

RESULTS

Bone metastases were confirmed in six patients. 18 F-FDG PET/CT was true positive in two and false negative in four patients. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 18 F-FDG PET/CT were 33.33, 93.33, 66.67, 77.78, and 76.19%, respectively (95% confidence interval). The tendency of ILC osseous metastases to be more sclerotic explains the low diagnostic accuracy of 18 F-FDG PET/CT in detection of bone metastases, making it a less suited method of evaluation.

CONCLUSION

The results of the present study indicate that 18 F-FDG PET/CT has a low diagnostic accuracy in detecting bone metastases in lobular breast cancer and, by inference, new functional modalities can be explored in these patients. The findings contribute valuable insights to optimize the integration of molecular imaging into the diagnostic algorithm for this specific breast cancer subtype.

Clinically node-negative invasive lobular carcinoma of the breast showing multiple lymph node metastases

A 73-year-old woman was pointed out of her right breast tumor on screening computed tomography (CT). Mammography showed distortion of the mammary gland and skin retraction. Ultrasound (US) showed an irregular tumor with hyperechoic haloes adjacent to the anterior tumor borders. Neither lymphadenopathy nor image findings suggesting lymph node metastasis were detected on US and CT. Core needle biopsy pathologically showed the tumor to be invasive lobular carcinoma. Under the preoperative diagnosis of node-negative breast cancer, the patient underwent mastectomy and sentinel node biopsy. Due to no sentinel node detection, a small but hard lymph node was identified and submitted for frozen section as a sampling node. After confirming the lymph node metastasis on frozen section, axillary lymph node dissection revealed 12 lymph node metastases. Postoperative pathological study showed cancer cell infiltration to the dermis near the nipple-areolar complex. In addition, immmunostaining showed the tumor to have low proliferative biology, i.e., Ki-67 labelling index of 10%. Breast surgeons should note that indolent invasive lobular carcinoma with cancer cell infiltration to the skin near the nipple-areolar complex can have multiple lymph node metastases even though showing neither lymphadenopathy nor image findings suggesting lymph node metastasis.

Genomic profiling and pre-clinical modelling of breast cancer leptomeningeal metastasis reveals acquisition of a lobular-like phenotype

Breast cancer leptomeningeal metastasis (BCLM), where tumour cells grow along the lining of the brain and spinal cord, is a devastating development for patients. Investigating this metastatic site is hampered by difficulty in accessing tumour material. Here, we utilise cerebrospinal fluid (CSF) cell-free DNA (cfDNA) and CSF disseminated tumour cells (DTCs) to explore the clonal evolution of BCLM and heterogeneity between leptomeningeal and extracranial metastatic sites. Somatic alterations with potential therapeutic actionability were detected in 81% (17/21) of BCLM cases, with 19% detectable in CSF cfDNA only. BCLM was enriched in genomic aberrations in adherens junction and cytoskeletal genes, revealing a lobular-like breast cancer phenotype. CSF DTCs were cultured in 3D to establish BCLM patient-derived organoids, and used for the successful generation of BCLM in vivo models. These data reveal that BCLM possess a unique genomic aberration profile and highlight potential cellular dependencies in this hard-to-treat form of metastatic disease.

Evaluation of Treatment Response in Patients with Breast Cancer

Breast cancer (BC) remains one of the leading causes of death among women. The management and outcome in BC are strongly influenced by a multidisciplinary approach, which includes available treatment options and different imaging modalities for accurate response assessment. Among breast imaging modalities, MR imaging is the modality of choice in evaluating response to neoadjuvant therapy, whereas F-18 Fluorodeoxyglucose positron emission tomography, conventional computed tomography (CT), and bone scan play a vital role in assessing response to therapy in metastatic BC. There is an unmet need for a standardized patient-centric approach to use different imaging methods for response assessment.

FDG and Non-FDG Radiopharmaceuticals for PET Imaging in Invasive Lobular Breast Carcinoma

Invasive lobular cancer (ILC) is the second most frequent histological type of breast cancer (BC) and includes a heterogeneous spectrum of diseases with unique characteristics, especially the infiltrative growth pattern and metastatic spread. [¹⁸F]fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) is extensively used in oncology and BC patient evaluation. Its role in ILCs is considered suboptimal due to its low FDG avidity. Therefore, ILCs could benefit from molecular imaging with non-FDG tracers that target other specific pathways, contributing to precision medicine. This narrative review aims to summarize the current literature on the use of FDG-PET/CT in ILC and to discuss future opportunities given by the development of innovative non-FDG radiotracers.

Performance of [18F]FDG-PET/CT Imaging in First Recurrence of Invasive Lobular Carcinoma

BACKGROUND

Invasive lobular carcinoma accounts for 10 to 15% of all breast cancers. The first objective of this retrospective study was to assess the diagnostic performance of FDG-PET/CT scanning in women previously treated for invasive lobular carcinoma with suspected first recurrence. The secondary objectives were to evaluate the impact of PET/CT in a change in treatment and its prognostic value on specific survival.

METHODS

Patients in whom a PET/CT scan was performed from January 2011 to July 2019 in our Cancer Research Center were enrolled. Recurrence was suspected based on clinical symptoms, abnormal findings on conventional imaging, and/or elevated tumor markers. The diagnosis of recurrence was established by the oncologist after integration of all clinical, biological, histological, imaging, and follow-up data. Prognostic factors of recurrence as predicted by PET were determined using univariate logistic regression. KI67, mitotic index, or grade of mitosis were tested. Survival curves were compared using the log-rank test. Sixty-four patients (mean age: 60.3; SD = 12.4 years) were enrolled. The average time from initial diagnosis of the primary tumor to suspicion of recurrence was 5.2 ± 4.1 years. Forty-eight patients (75%) were judged to have recurrence by the oncologist: 7 local and 41 metastatic, with mainly bone (n = 24), lymph node (n = 14) and liver (n = 10) metastases.

RESULTS

Sensitivity, specificity, and positive and negative predictive values of PET/CT to predict recurrence were, respectively: 87%, 87%, 95%, and 70%. SUVmax at recurrence sites was generally high (mean: 6.4; SD = 2.9). False negative PET/CT results occurred with local (n = 2), peritoneal (n = 2), meningeal (n = 1), or bladder (n = 1) recurrences. In 40 patients with available histopathological data from suspected sites of recurrence, 30 PET/CT were true positive. In four patients, primary lung (n = 1) or gastric (n = 1) tumors or lymphomas (n = 2) were found. The detection of a recurrence resulted in a change in treatment in 44/48 patients (92%). No association between recurrence predicted by PET and biological biomarkers was found. Median specific survival appears shorter in patients with metastatic recurrence versus patients with local or no recurrence on PET/CT (p = 0.067).

CONCLUSIONS

FDG-PET/CT is an effective and reliable tool for the detection of invasive lobular carcinoma recurrence, although certain recurrence sites specific to this histological type can impair its diagnostic performance.

Current and future diagnostic and treatment strategies for patients with invasive lobular breast cancer

BACKGROUND

Invasive lobular breast cancer (ILC) is the second most common type of breast cancer after invasive breast cancer of no special type (NST), representing up to 15% of all breast cancers.

DESIGN

Latest data on ILC are presented, focusing on diagnosis, molecular make-up according to the European Society for Medical Oncology Scale for Clinical Actionability of molecular Targets (ESCAT) guidelines, treatment in the early and metastatic setting and ILC-focused clinical trials.

RESULTS

At the imaging level, magnetic resonance imaging-based and novel positron emission tomography/computed tomography-based techniques can overcome the limitations of currently used imaging techniques for diagnosing ILC. At the pathology level, E-cadherin immunohistochemistry could help improving inter-pathologist agreement. The majority of patients with ILC do not seem to benefit as much from (neo-)adjuvant chemotherapy as patients with NST, although chemotherapy might be required in a subset of high-risk patients. No differences in treatment efficacy are seen for anti-human epidermal growth factor receptor 2 (HER2) therapies in the adjuvant setting and cyclin-dependent kinases 4 and 6 inhibitors in the metastatic setting. The clinical utility of the commercially available prognostic gene expression-based tests is unclear for patients with ILC. Several ESCAT alterations differ in frequency between ILC and NST. Germline BRCA1 and PALB2 alterations are less frequent in patients with ILC, while germline CDH1 (gene coding for E-cadherin) alterations are more frequent in patients with ILC. Somatic HER2 mutations are more frequent in ILC, especially in metastases (15% ILC versus 5% NST). A high tumour mutational burden, relevant for immune checkpoint inhibition, is more frequent in ILC metastases (16%) than in NST metastases (5%). Tumours with somatic inactivating CDH1 mutations may be vulnerable for treatment with ROS1 inhibitors, a concept currently investigated in early and metastatic ILC.

CONCLUSION

ILC is a unique malignancy based on its pathological and biological features leading to differences in diagnosis as well as in treatment response, resistance and targets as compared to NST.

Does the addition of whole-body MRI to routine imaging influence real-world treatment decisions in metastatic breast cancer?

Background

The assessment of metastatic breast cancer (MBC) can be limited with routine imaging such as computed tomography (CT) especially in bone-only or bone-predominant disease. This analysis investigates the effects of the use of WBMRI in addition to the use of routine CT, bone scintigraphy (BS) and fluorine-18-fluorodeoxyglucose positron emission tomography with computed tomography (FDG-PET/CT) on influencing systemic anti-cancer treatment (SACT) decisions in patients with known MBC.

Methods

MBC patients undergoing SACT who had WBMRI undertaken within 8 weeks of either a routine CT, BS or FDG-PET/CT were reviewed retrospectively. The clinical indications for undertaking the WBMRI examinations were recorded. Data on the extent and distribution of the disease were collected and discordance/concordance of disease status across the imaging modalities were compared. SACT decisions at each time point were also evaluated.

Results

There were 105 MBC patients with 148 WBMRI studies paired with CT, BS or FDG-PET/CT. 50 pairs (33.8%) showed differences in the extent of disease, with 44 pairs due to additional sites (AS) reported on WBMRI alone.

81 patients (Group 1) had one WBMRI paired with routine imaging due to a variety of indications, with clinical symptoms (such as bone pain) being the most common (24.7%).

24 patients (Group 2) had more than one WBMRI study paired with routine imaging comprising 67 pairs. 13/67 pairs (19.4%) showed discordance in assessments. 10/13 pairs had progressive disease (PD) reported on WBMRI alone.

SACT change due to AS reported on WBMRI alone occurred in 21/23 pairs (91.3%) in Group 1. SACT change due to PD reported on WBMRI alone in Group 2 occurred in 6/14 pairs (42.9%). SACT change due to AS/PD in both groups occurred in 11/102 pairs (10.8%) with known invasive ductal carcinoma (IDC) and 13/28 pairs (46.4%) with invasive lobular carcinoma (ILC).

Conclusions

The use of WBMRI in MBC led to earlier recognition of PD and SACT change compared with the other imaging modalities. A higher proportion of discordant response assessments and SACT changes were observed in ILC compared with IDC in our patient group, although larger-scale studies are required to investigate this further.

Biomarker profile of invasive lobular carcinoma: pleomorphic versus classic subtypes, clinicopathological characteristics and prognosis analyses

PURPOSE

To compare the clinicopathologic features and prognosis of pleomorphic invasive lobular carcinoma (P-ILC) and classic ILC (C-ILC) according to the biomarker profile.

METHODS

A total of 667 C-ILCs and 133 P-ILCs between 2011 and 2021 were included. Clinicopathologic features and stromal tumor-infiltrating lymphocytes (sTILs) status were evaluated. P-ILCs were divided into subtypes based on ER/PR and HER2 expression. The overall survival and disease-free survival (DFS) of patients were compared among matched P-ILCs, C-ILCs, and invasive ductal carcinomas (IDCs) with biomarker subtypes.

RESULTS

Compared to C-ILCs, P-ILCs had greater tumor sizes and stages, fewer ER-positive, more HER2-positive, triple negative (TN), and Ki-67 > 20% tumors (P < 0.05). P-ILCs were subdivided into ER+ (63.1%), HER2+ (21.1%) and TN (15.8%). ER+ P-ILCs were mainly showed trabecular and solid growth patterns. Apocrine and solid features were more strongly associated with HER2+ P-ILCs and TN-P-ILCs, respectively. The prognosis of each biomarker group (ER+, HER2+ and TN) differed by subtype. The P-ILC biomarker subtypes had worse prognosis than the same subtypes in the IDC group, while there was no difference between the P-ILC and the C-ILC counterparts. Solid variants of P-ILC had the worst prognosis. Bone was the most common metastatic site in ER+ P-ILCs and TN-P-ILCs. HER2+ P-ILCs tended to metastasize to the brain and liver. DFS of HER2+ P-ILCs and TN-P-ILCs were worse than that of ER+ P-ILCs. Lacking lobular carcinoma in situ and sTILs ≤ 10% were associated with worse survival of ER+ P-ILCs and TN-P-ILCs, respectively. For HER2+ P-ILCs, Ki-67 > 20% and sTILs ≤ 10% were significant factors for lower DFS.

CONCLUSION

P-ILCs is an aggressive subtype of ILCs. Analyzing the prognostic factors of P-ILCs with heterogeneous morphological and biomarker characteristics is helpful for creating an individualized treatment.

A review on the added value of whole-body MRI in metastatic lobular breast cancer

Invasive lobular breast carcinomas (ILC) account for approximately 15% of breast cancer diagnoses. They can be difficult to diagnose both clinically and radiologically, due to their infiltrative growth pattern. The pattern of metastasis of ILC is unusual, with spread to the serosal surfaces (pleura and peritoneum), retroperitoneum and gastrointestinal (GI)/genitourinary (GU) tracts and a higher rate of leptomeningeal spread than IDC. Routine staging and response assessment with computed tomography (CT) can be undertaken quickly and measurements can be reproduced easily, but this is challenging with metastatic ILC as bone-only/bone-predominant patterns are frequently seen and assessment of the disease status is limited in these scenarios. Functional imaging such as whole-body MRI (WBMRI) allows the assessment of bone and soft tissue disease by providing functional information related to differences in cellular density between malignant and benign tissues. A number of recent studies have shown that WBMRI can detect additional sites of disease in metastatic breast cancer (MBC), resulting in a change in systemic anti-cancer therapy. Although WBMRI and fluorodeoxyglucose-positron-emission tomography-computed tomography (FDG-PET/CT) have a comparable performance in the assessment of MBC, WBMRI can be particularly valuable as a proportion of ILC are non-FDG-avid, resulting in the underestimation of the disease extent. In this review, we explore the added value of WBMRI in the evaluation of metastatic ILC and compare it with other imaging modalities such as CT and FDG-PET/CT. We also discuss the spectrum of WBMRI findings of the different metastatic sites of ILC with CT and FDG-PET/CT correlation. KEY POINTS: • ILC has an unusual pattern of spread compared to IDC, with metastases to the peritoneum, retroperitoneum and GI and GU tracts, but the bones and liver are the commonest sites. • WBMRI allows functional assessment of metastatic disease, particularly in bone-only and bone-predominant metastatic cancers such as ILC where evaluation with CT can be challenging and limited. • WBMRI can detect more sites of disease compared with CT, can reveal disease progression earlier and provides the opportunity to change ineffective systemic treatment sooner.

De novo metastatic lobular breast carcinoma: A population-based study from SEER database

PURPOSE

Patients with metastatic lobular breast carcinoma constitute a heterogeneous group with distinguishing features. Our aim was to describe the features and survival of them, and further subdivide them into subcategories for prognostic stratification and treatment planning.

PATIENTS AND METHODS

Patients with de novo metastatic breast cancer from 2010 to 2018 were identified using the SEER database. Multivariate logistic regression analysis was conducted to calculate odds ratios. The within-pair difference was minimized by propensity score matching. Multiple comparisons based on Cox proportional hazards model were performed to investigate the interactions of M1 subcategory and treatment modality on survival.

RESULTS

A total of 1,675 patients with de novo metastatic lobular breast carcinoma were identified, they were more likely to have HR+/HER2- subtype, low histologic grade, low T/N stage, fewer metastatic sites, but worse prognosis compared with patients with metastatic ductular breast carcinoma. The M1 stage was subdivided into 3 subcategories with significantly different prognoses. The benefits of primary tumor surgery were more pronounced in M1a/b disease, whereas the benefits of chemotherapy increased with the progression of metastatic disease.

CONCLUSION

Patients with metastatic lobular breast carcinoma have unique clinicopathological characteristics and metastatic patterns. M1 subcategory assists prognosis stratification and treatment planning for such patients.

Infiltrative pattern of metastatic invasive lobular breast carcinoma in the abdomen: a pictorial review

Invasive lobular carcinoma (ILC) has a greater tendency to metastasize to the peritoneum, retroperitoneum, and gastrointestinal (GI) tract as compared to invasive carcinoma of no special type (NST). Like primary ILC in the breast, ILC metastases are frequently infiltrative and hypometabolic, rather than mass forming and hypermetabolic in nature. This renders them difficult to detect on conventional and metabolic imaging studies. As a result, intra-abdominal ILC metastases are often detected late, with patients presenting with clinical complications such as liver failure, hydronephrosis, or bowel obstruction. In patients with known history of ILC, certain imaging features are very suggestive of infiltrative metastatic ILC. These include retroperitoneal or peritoneal nodularity and linitis plastica appearance of the bowel. Recognition of linitis plastica on imaging should prompt deep or repeat biopsies. In this pictorial review, the authors aim to familiarize readers with imaging features and pitfalls for evaluation of intra-abdominal metastatic ILC. Awareness of these will allow the radiologist to assess these patients with a high index of suspicion and aid detection of metastatic disease. Also, this can direct histopathology and immunohistochemical staining to obtain the correct diagnosis in suspected metastatic disease.

Metastatic invasive lobular breast cancer presenting as linitis plastica of the colon: Tumour characterization using [18 F]FES PET/MRI

Metastatic invasive lobular breast cancer (ILC) to the colon is rare and usually ER-positive. We present an ER-negative case of metastatic ILC presenting as linitis plastica of the colon where [¹⁸ F]FES PET/MRI allowed the evaluation of the ER phenotypic transformation in the colonic metastasis from the ER-positive breast ILC in vivo.

Pleomorphic Invasive Lobular Cancer of the Breast Presenting with Orbital Metastasis: A Case Report

BACKGROUND

Orbital metastasis of breast cancer is an unusual condition, especially in the absence of a previous diagnosis of primary breast cancer. The main MRI findings in patients with orbital metastasis are retroorbital soft tissue with thickening of extraocular muscles. Paradoxical enophtalmos secondary to fibrosis can be seen.

CASE REPORT

In this case report we present a 75-year-old female patient with left eye pain and blurred vision and retraction. Although there was no evidence of malignancy in the biopsy of the orbita; since the patient's complaints continued despite idiopathic pseudotumor treatment; mammography was recommended to rule out the possibility of breast cancer metastasis. Her mammography revealed a suspicious lesion in the left breast and proved to be pleomorphic invasive lobular cancer.

CONCLUSION

Breast cancer metastasis should be kept in mind in women with pseudotumor -like involvement of the orbita.

Diagnostic utility of the combined use of HNF4A and GATA3 in distinction between primary and metastatic breast and gastric carcinomas

Sometimes the distinction between gastric adenocarcinomas and breast carcinomas can be challenging. Hepatocyte nuclear factor 4-alpha (HNF4A) has been suggested as a potential marker in these cases. The aim of the present work was to evaluate the role of the combined use of HNF4A and GATA3 as immunohistochemical markers in distinction between primary and metastatic breast and gastric carcinomas. This retrospective study was conducted on (81) cases divided into four groups of cohorts: primary BC (cohort I, n = 25), primary GC (cohort II, n = 23), and metastases derived from both types of tumors designated as metastasis derived from BC (cohort III-A, n = 17) and metastasis derived from GC (cohort III-B, n = 16). We performed immunohistochemistry analysis of HNF4A and GATA3 in all (81) cases. HNF4A expression was seen in 22 of 23 primary gastric adenocarcinomas and was absent in all 25 primary breast carcinomas (sensitivity 95.7%, specificity 100%). HNF4A was seen in 15 of 16 metastatic gastric adenocarcinomas and was absent in all 17 metastatic breast carcinomas (sensitivity 93.8%, specificity 100%). GATA3 showed 92 and 88% sensitivity, and 95.7 and 100% specificity for primary breast carcinomas and metastatic breast carcinomas, respectively. Our data confirmed the potential utility of HNF4A as a diagnostic marker and can be used as an adjunct to GATA3 as an immunohistochemical panel to differentiate between breast and gastric carcinomas.

Impact of Hepatic Metastasectomy in the Multimodal Treatment of Metastatic Breast Cancer

BACKGROUND

Surgical management of hepatic metastases in patients with stage IV breast cancer remains controversial. The purpose of this study was to examine the impact of hepatic metastasectomy on long-term outcomes.

METHODS

The 2004-2015 National Cancer Database was queried for all patients diagnosed with stage IV breast cancer with metastases isolated to the liver. Patient demographics, disease-, treatment- and outcome-related data were analyzed.

RESULTS

Of 2,895 patients, only 90 (3.1%) underwent hepatic resection. Compared to patients who did not undergo metastasectomy, patients treated with metastasectomy tended to be younger (52 ± 12.7 versus 59.2 ± 14.6; P < 0.001) and have private insurance (74.4% versus 45.3%; P < 0.001). Independent predictors of metastasectomy included younger age (OR 0.98; CI 0.96-0.99; P = 0.01), lobular carcinoma (OR 2.26; CI 1.06-4.82; P = 0.03), and prior surgery of the primary site (partial mastectomy (OR 6.96; CI 3.47-13.95; P < 0.001) or total mastectomy (OR 5.74; CI 3.06-10.76; P < 0.001)). Compared to no metastasectomy, hepatic metastasectomy was independently associated with a 37% reduction in the risk of death (HR 0.63; CI 0.44-0.91; P = 0.01).

CONCLUSIONS

Stage IV breast cancer with metastases to the liver is rare and few patients undergo hepatic resection. However, in this select patient population, hepatic metastasectomy was associated with a significant survival advantage when included in the multimodal treatment of synchronous stage IV breast cancer.

Skin Nodules as a First Presentation of Synchronous Bilateral Invasive Lobular Breast Carcinoma: A Case Report

The most common cause of skin metastases in adult women is primary breast carcinoma, which comprises about 70% of cases [1]. Skin metastases have non-specific clinical appearances, making it challenging to differentiate them from other benign conditions [1]. We present a case of a 52-year-old female with type II diabetes and a three-month history of refractory skin lesions who did not respond to anti-inflammatory treatment. The patient subsequently complained of a right breast lump, evaluation of which led to the diagnosis of bilateral synchronous invasive lobular carcinoma.

Leptomeningeal Metastasis in ER + HER2- Advanced Breast Cancer Patients: A Review of the Cases in a Single Institute Over a 15-year Period

PURPOSE

While leptomeningeal metastasis (LM) from estrogen receptor-positive, HER2-negative advanced breast cancer (ER + HER2-ABC) has a poor prognosis, the details of ER + HER2-LM are unclear. We therefore retrospectively investigated patients with LM from ER + HER2-ABC.

METHODS

ER + HER2-ABC patients who received any therapy at Shizuoka Cancer Center between October 2002 and December 2017 were retrospectively analyzed. Patients with central nervous system (CNS) metastases were divided into three groups: brain metastasis (BM) only (B group); BM with LM (BL group); and LM only (L group).

RESULTS

Among 369 patients, 102 developed CNS metastases: 70 (68.6%), 13 (12.8%), and 19 (18.6%) in the B, BL, and L groups, respectively. The L group showed a later onset, poorer performance status, more symptoms, and more skull metastasis than the other groups. Radiotherapy as the initial treatment was introduced to 13/13 (100%) and 15/19 (78.9%) in the BL and L groups, respectively. Subsequent systemic therapy excluding best supportive care was introduced to 5/13 (38.5%) and 5/19 (26.3%) in the BL and L groups, respectively. The median overall survival from the diagnosis of CNS lesions was 295.0, 146.0, and 99.0 days in the B, BL, and L groups, respectively, and worsening of CNS lesions was the major cause of death in the BL and L groups. Multivariate analyses showed that concurrent soft tissue metastasis (hazard ratio, 4.620) and subsequent systemic therapy (hazard ratio, 0.063) were prognostic for the L group.

CONCLUSION

Management of LM from ER + HER2-ABC remains challenging, so a multimodal approach with novel systemic therapy is warranted.

A rare case of lobular breast cancer metastasizing to large bowel

Lobular breast cancer metastasis to bowel is rare, however, when it occurs, the prognosis is poor. Possible benefits of investigation with screening endoscopy for gastrointestinal metastases are discussed in order to optimize prognosis for patients.

Unilateral Orbital Metastasis as the Unique Symptom in the Onset of Breast Cancer in a Postmenopausal Woman: Case Report and Review of the Literature

The orbit represents an unusual metastases site for patients diagnosed with cancer, however, breast cancer is the main cause of metastases at this level. These orbital metastases were discovered in patients with a history of breast cancer as unique or synchronous lesions. We present a rare case of a unique retroocular metastasis as the first initial symptom of a tubulo-lobular mammary carcinoma in a postmenopausal woman. A 57-year-old patient complains of diplopia, diminishing visual acuity, orbital tenderness, slight exophthalmia and ptosis of the left eyelid, with insidious onset. Clinical examination and subsequent investigations revealed a left breast cancer cT2 cN1 pM1 stage IV. Breast conserving surgery was performed on the left breast. Pathological examination with immunohistochemistry staining established the complete diagnostic: pT2pN3aM1 Stage IV breast cancer, luminal B subtype. After two years from the initial breast cancer diagnosis, the patient was diagnosed by the psychiatrist with a depressive disorder and was treated accordingly. Orbital metastases are usually discovered in known breast cancer patients and they are found in the context of a multi-system end-stage disease. Most reports cite that up to 25% of the total orbital metastases cases are discovered before the diagnosis of the primary tumor, as our case did. MRI is the gold standard for evaluating orbital tumors. The ILC histological subtype metastasizes in the orbitals more frequently than invasive ductal carcinoma. The prognosis of patients with orbital metastases is poor. The median survival after diagnosis of orbital metastases from a breast cancer primary is ranging from 22 to 31 months. Overall survival of our patient was 56 months, longer than the median survival reported in literature. Orbital metastases must be taken into account when patients accuse ophthalmologic symptoms even in the absence of a personal history of cancer. Objective examination of every patient that incriminates these types of symptoms is essential, and breast palpation must be made in every clinical setting. Orbital biopsy is necessary for the confirmation of the diagnosis and for an adequate treatment. Although recommendations for management of orbital metastases are controversial, it appears that multidisciplinary treatment of both metastases and primary cancer improves overall survival.

Gastric metastases from invasive lobular carcinoma of the breast: Case report

Invasive lobular carcinoma is the second most common type of invasive carcinoma of the breast. Although rare, invasive lobular carcinoma can lead to gastric metastases, which may appear several years after the initial diagnosis. The diagnosis is difficult, either because of its rarity or because of overlapping symptoms and imaging findings with primary gastric carcinoma. Immunohistochemistry is the key to diagnosis. We report a case of a 40-year-old woman with a previous history of invasive lobular carcinoma of the breast 2 years before, who presented recurrent and nonspecific gastrointestinal symptoms. Imaging findings revealed linitis plastica and the biopsy showed the presence of signet ring cell neoplasia. After gastrectomy, immunohistochemistry demonstrated diffuse expression of GATA-3 and the presence of estrogen receptors in some neoplastic cells with CK20^-, leading to the final diagnosis of gastric metastases from invasive lobular carcinoma of the breast.

Asymptomatic solitary metastasis to the stomach from breast cancer: A case report

Distant metastases from breast cancer are frequently found in bones, lungs and the liver. Metastasis to the stomach is rare, and its clinical presentation remains unclear. The present report describes a case of isolated gastric metastasis from breast cancer identified by contrast-enhanced computed tomography (CT). A 45-year-old female patient underwent right mastectomy and axillary lymph node dissection after preoperative chemotherapy for right invasive lobular breast carcinoma T4bN2M0, stage IIIB. Postoperative radiotherapy and endocrine therapy with tamoxifen for 5 years were performed. CT for postoperative follow-up at 52 years old revealed thickening of the stomach wall. Although the patient was asymptomatic, erosive mucosa was observed on the gastric body during gastroscopy. The gastric lesion was immunohistochemically diagnosed as metastatic luminal disease from the breast cancer. Positron emission tomography/CT revealed no abnormal accumulation suggesting metastasis to other organs. Palbociclib and fulvestrant treatment were initiated for gastric metastasis. Invasive lobular breast carcinoma results in gastrointestinal metastasis, including the stomach, more frequently than invasive ductal breast carcinoma. However, most gastric metastases occur simultaneously with systemic metastases. Solitary metastasis to the stomach without symptoms as in this case has rarely been reported. The possibility of gastric metastasis should be considered among the differential diagnoses, even in the absence of symptoms, when gastrointestinal abnormalities are seen on CT in patients with a history of breast cancer.

Head-to-Head Evaluation of 18F-FES and 18F-FDG PET/CT in Metastatic Invasive Lobular Breast Cancer

Invasive lobular carcinoma (ILC) demonstrates lower conspicuity on ¹⁸F-FDG PET than the more common invasive ductal carcinoma. Other molecular imaging methods may be needed for evaluation of this malignancy. As ILC is nearly always (95%) estrogen receptor (ER)-positive, ER-targeting PET tracers such as 16α-¹⁸F-fluoroestradiol (¹⁸F-FES) may have value. We reviewed prospective trials at Memorial Sloan Kettering Cancer Center using ¹⁸F-FES PET/CT to evaluate metastatic ILC patients with synchronous ¹⁸F-FDG and ¹⁸F-FES PET/CT imaging, which allowed a head-to-head comparison of these 2 PET tracers. Methods: Six prospective clinical trials using ¹⁸F-FES PET/CT in patients with metastatic breast cancer were performed at Memorial Sloan Kettering Cancer Center from 2008 to 2019. These trials included 92 patients, of whom 14 (15%) were of ILC histology. Seven of 14 patients with ILC had ¹⁸F-FDG PET/CT performed within 5 wk of the research ¹⁸F-FES PET/CT and no intervening change in management. For these 7 patients, the ¹⁸F-FES and ¹⁸F-FDG PET/CT studies were analyzed to determine the total number of tracer-avid lesions, organ systems of involvement, and SUV_max of each organ system for both tracers. Results: In the 7 comparable pairs of scans, there were a total of 254 ¹⁸F-FES-avid lesions (SUV_max, 2.6-17.9) and 111 ¹⁸F-FDG-avid lesions (SUV_max, 3.3-9.9) suggestive of malignancy. For 5 of 7 (71%) ILC patients, ¹⁸F-FES PET/CT detected more metastatic lesions than ¹⁸F-FDG PET/CT. In the same 5 of 7 patients, the SUV_max of ¹⁸F-FES-avid lesions was greater than the SUV_max of ¹⁸F-FDG-avid lesions. One patient had ¹⁸F-FES-avid metastases with no corresponding ¹⁸F-FDG-avid metastases. There were no patients with ¹⁸F-FDG-avid distant metastases without ¹⁸F-FES-avid distant metastases, although in one patient liver metastases were evident on ¹⁸F-FDG but not on ¹⁸F-FES PET. Conclusion: ¹⁸F-FES PET/CT compared favorably with ¹⁸F-FDG PET/CT for detection of metastases in patients with metastatic ILC. Larger prospective trials of ¹⁸F-FES PET/CT in ILC should be considered to evaluate ER-targeted imaging for clinical value in patients with this histology of breast cancer.

Patient treatment and outcome after breast cancer orbital and periorbital metastases: a comprehensive case series including analysis of lobular versus ductal tumor histology

BACKGROUND

Breast cancer is the most common malignancy to spread to the orbit and periorbit, and the invasive lobular carcinoma (ILC) histologic subtype of breast cancer has been reported to form these ophthalmic metastases (OM) more frequently than invasive ductal carcinomas (IDC). We herein report our single academic institution experience with breast cancer OM with respect to anatomical presentation, histology (lobular vs. ductal), treatment, and survival.

METHODS

We employed the natural language processing platform, TIES (Text Information Extraction System), to search 2.3 million de-identified patient pathology and radiology records at our institution in order to identify patients with OM secondary to breast cancer. We then compared the resultant cohort, the "OM cohort," to two other representative metastatic breast cancer patient (MBC) databases from our institution. Histological analysis of selected patients was performed.

RESULTS

Our TIES search and manual refinement ultimately identified 28 patients who were diagnosed with breast cancer between 1995 and 2016 that subsequently developed OM. Median age at diagnosis was 54 (range 28-77) years of age. ER, PR, and HER2 status from the 28 patients with OM did not differ from other patients with MBC from our institution. The relative proportion of patients with ILC was significantly higher in the OM cohort (32.1%) than in other MBC patients in our institution (11.3%, p = 0.007). Median time to first OM in the OM cohort was 46.7 months, and OM were the second most frequent first metastases after bony metastases. After diagnosis of the first distant metastasis of any kind, median survival of patients with ILC (21.4 months) was significantly shorter than that of patients with IDC (55.3 months, p = 0.03). Nine patients developed bilateral OM. We observed a significant co-occurrence of OM and central nervous system metastases (p = 0.0053). The histological analysis revealed an interesting case in which the primary tumor was of a mixed ILC/IDC subtype, while only ILC was present in the OM.

CONCLUSIONS

OM from breast cancer are illustrative of the difference in metastatic behavior of ILC versus IDC and should be considered when treating patients with ILC, especially in those with complaints of visual acuity changes.

Mediastinal and retroperitoneal fibrosis as a manifestation of breast cancer metastasis: A case report and literature review

RATIONALE

Mediastinal and retroperitoneal fibrosis as a manifestation of metastasis from malignancies is rare disease and particularly, cases of mediastinal fibrosis have been rarely reported.

PATIENT CONCERNS

A 60-year-old woman presented with dyspnea and bilateral flank pain. The patient had no previous history of malignancy.

DIAGNOSES

A contrast-enhanced chest computed tomography scan revealed a left breast mass and infiltrative soft tissue masses in the mediastinum and retroperitoneum, which showed high fluorodeoxyglucose uptake on positron emission tomography scan. The left breast mass was proven as a malignancy on biopsy and surgical excisional biopsy of the mediastinal mass revealed metastasis from the breast cancer on histopathologic examination.

INTERVENTIONS

Our patient was treated with palliative hormone therapy for the primary breast cancer and metastasis with mediastinal and retroperitoneal fibrosis.

OUTCOMES

Follow-up imaging studies showed improvement of the primary breast cancer and also metastasis.

LESSONS

We report this rare case to emphasize that mediastinal and retroperitoneal fibrosis can be a presentation of metastasis from various primary malignancies. We expect that appropriate diagnosis and treatment for metastatic mediastinal and retroperitoneal fibrosis can have a beneficial effect on disease course and prognosis of the patient.

Differentiating breast carcinoma with signet ring features from gastrointestinal signet ring carcinoma: assessment of immunohistochemical markers

Signet ring morphology is recognized throughout the gastrointestinal tract. However, this pattern may be observed in other primary sites giving rise to diagnostic challenges in the work-up of metastases. Relatively newer immunohistochemical markers have not been evaluated in this context. We assessed expression patterns of several common immunohistochemical markers in tumors with Signet ring morphology to delineate a pragmatic approach to this differential diagnosis. Primary breast and gastrointestinal carcinomas showing Signet ring features were reviewed. Non-mammary and non-gastrointestinal tumors with this morphology were included for comparison. Estrogen receptor (ER), progesterone receptor (PR), E-cadherin, CK7, CK20, GCDFP-15, mammaglobin, CDX2, GATA-3, and HepPar-1 immunohistochemistry was performed. Expression patterns were compared between breast and gastrointestinal tumors as well as lobular breast and gastric tumors. Ninety-three cases were identified: 33 breast carcinomas including 13 lobular, 50 gastrointestinal tumors including 23 gastric, and 10 from other sites. ER (sensitivity=81.8%, specificity=100%, positive predictive value (PPV)=100%, negative predictive value (NPV)=89.3%) and GATA-3 (sensitivity=100%, specificity=98%, PPV=96.8%, NPV=100%) expression were associated with breast origin. CK20 (sensitivity=66.7%, specificity=93.3%, PPV=94.1%, NPV=63.6%) and CDX2 (sensitivity=72%, specificity=100%, PPV=100%, NPV=68.9%) demonstrated the strongest discriminatory value for gastrointestinal origin. These markers exhibited similar discriminatory characteristics when comparing lobular and gastric signet ring carcinomas. In a limited trial on metastatic breast and gastric cases, these markers successfully discriminated between breast and gastric primary sites in 15 of 16 cases. ER and GATA-3 are most supportive of mammary origin and constitute an effective panel for distinguishing primary breast from primary gastrointestinal Signet ring tumors when combined with CK20 and CDX2 immunohistochemistry.

Molecular Classification of Breast Cancer

Breast cancer is a heterogeneous disease, observed traditionally by morphology and protein expression but, more recently with the advent of modern molecular technologies, at the genomic and transcriptomic level. This review describes the association between the different molecular subtypes with the histologic subtypes of breast cancer alongside some of their major genomic characteristics and illustrates how these subtypes may affect the appearance of tumors on imaging studies. The authors aim to show how molecular stratification can be used to augment traditional methods to improve our understanding of breast cancers and their clinical management.

Orbital metastasis from an occult breast carcinoma (T0, N1, M1)

The authors report a case of an orbital metastasis from an occult breast carcinoma. A 66-year-old woman presented with a growing left orbital tumour. Orbital CT scan was consistent with lymphoma. However, ocular pathology revealed small neoplastic cells showing an 'indian file pattern' suggestive of metastatic carcinoma and immunohistochemistry was positive for CK7, CK CAM5.2 and oestrogen receptor. A systemic evaluation was then performed with mammogram, breast ultrasound and MRI considered normal. An exhaustive systemic evaluation revealed multiple bone lesions, a right axillary lymph node lesion, which presented the same pattern on pathology and immunohistochemistry, with no evidence of a primary tumour. A diagnosis of a metastatic lobular carcinoma of the breast (T0, N1, M1) was made and the patient was started on chemotherapy and adjuvant hormonal therapy.

The value of 18F-FDG PET/CT imaging in breast cancer staging

The National Comprehensive Cancer Network (NCCN) guidelines recommend assessment with positron emission tomography with 2-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography (18F-FDG PET/CT) in staging of breast cancer, starting from the stage IIIA. Previously, PET/CT contributed to the accurate staging from the stage IIB. Our aim is to evaluate the contribution of 18F-FDG PET/CT in staging of breast cancer patients. A total of 234 patients were retrospectively evaluated. PET/CT was performed preoperatively in 114/234 and postoperatively in 120/234 patients. Initial staging was performed based on histopathological results in 125/234 and clinical results in 109/234 patients, according to the American Joint Committee on Cancer (AJCC) classification. All patients had a normal abdominal ultrasound and chest x-ray. Following PET/CT imaging, modification in the staging was performed in patients with the metastatic findings. In 42/234 (17.9%) patients hypermetabolic extra-axillary regional lymph nodes and in 65/234 patients (27.7%) distant metastatic involvement were detected with PET/CT. Modification in the staging was applied in 82/234 (35%) patients. Patient management was changed in 69/234 (29.4%) cases. The percentage of patients with upstaging, according to each stage, was as follows: IIA: 18.6%, IIB: 30%, IIIA: 46.3%, IIIB: 68.8%, and IIIC: 20.8%. In 43/43 patients, 99mTc-methylene diphosphonate (MDP) bone scan did not show additional bone metastasis. In 5/32 patients, metastatic involvement was detected with sentinel lymph node biopsy (SLNB), but preoperative PET/CT scan did not reveal hypermetabolic lymph nodes. Although our study was limited by the referral bias and lack of homogeneity in the referral group, PET/CT still significantly contributed to the accurate staging and management of our breast cancer patients, starting from the stage IIA.

Bladder Metastases from Breast Cancer: Managing the Unexpected. A Systematic Review

Breast cancer (BrC) has the highest incidence among females world over and it is one of the most common causes of death from cancer overall. Its high mortality is mostly due to its propensity to rapidly spread to other organs through lymphatic and blood vessels in spite of proper treatment. Bladder metastases from BrC are rare, with 50 cases having been reported in the last 60 years. This review aims to discuss some critical points regarding this uncommon condition. First, we performed a systematic review of the literature in order to draw a clinical and pathological profile of this entity. On this basis, its features in terms of diagnostic issues, imaging techniques, and survival are critically examined. Most bladder metastases from BrC are secondary lobular carcinoma, which mimic very closely the rare variant of urothelial cancer with lobular carcinoma-like features (uniform cells with an uncohesive single-cell, diffusely invasive growth pattern); thus, immunohistochemistry is mandatory to arrive at a correct diagnosis. This article summarizes the current knowledge regarding the incidence, clinical presentation, diagnosis, prognosis, and treatment of bladder metastases in patients with BrC.

Periocular Breast Carcinoma Metastases: Predominant Origin From the Lobular Variant

PURPOSE

To further define the histopathologic features of breast carcinoma conducive to orbital metastasis.

METHODS

Ten new female patients with orbital or eyelid breast cancer metastases encountered between 2011 and 2016 had their medical records reviewed for determining their clinical characteristics. Microscopic glass slides from biopsies and immunohistochemical test results were also analyzed. Biomarkers studied included cytokeratin 7, nuclear estrogen and progesterone receptors, HER2, and E-cadherin.

RESULTS

All orbital metastatic lesions were lobular (nonductal) carcinomas that could arise as late as 24 years after the diagnosis of the primary breast tumors. The average age of patients at the time or orbital presentation was 64 years. Metastases were composed of small tumor cells with round, orthochromatic nuclei, and a small amount of cytoplasm. The cells were disposed in a variably fibrotic tumor-associated stroma. Two lesions were variants of lobular carcinoma-namely, alveolar and pleomorphic (the latter displaying cellular crowding, with some degree of nuclear atypia and less stroma). Three of the 9 orbital metastases presented with enophthalmos and 2 displayed euphthalmos despite variably sized orbital masses. In 2 cases, synchronous bilateral orbital metastases prevented any relative difference in globe position. Estrogen and progesterone receptors were usually detectable whereas E-cadherin could not be demonstrated.

CONCLUSIONS

Breast pathologists no longer refer to primary breast carcinomas and their orbital metastases as "scirrhous." It has been determined that the majority of orbital breast metastases are lobular carcinomas. This may be due to their lack of intercellular cohesiveness and the absence of E-cadherin which normally is expressed in many neoplastic cell types including ductal breast carcinomas, limiting their dispersion. In contrast, the majority of primary breast carcinomas are ductal. The ubiquitous collagenous matrix in breast metastases retracts, partially accounting for enophthalmos. The presence of euphthalmos despite an orbital mass additionally suggests some retraction of fibrous tissue (with or without fat atrophy) that suppresses relative proptosis. Metastatic lobular breast carcinoma is further implicated if there is a concomitant limitation in extraocular motility or vision decline.

Novel CT and scintigraphic findings of bone metastasis from invasive lobular breast cancer

INTRODUCTION

The aim of this study is to identify and describe the computed tomography and scintigraphic imaging patterns of osseous metastasis from invasive lobular breast cancer (ILC).

MATERIALS AND METHODS

CT and skeletal scintigraphy (SS) studies of 23 patients with diagnosis of ILC and osseous metastasis on their initial presentation were reviewed.

RESULTS

Osseous metastases in 14 patients (60.8%) appear as uniform small sclerotic lesions (USSL) on CT scan. The SS in these patients were interpreted as negative for metastasis (either normal or with some equivocal findings not typical for metastasis).

CONCLUSION

Osseous metastasis from ILC can have a characteristic imaging pattern on CT and SS. The pattern of USSL on CT scan with negative SS is highly suggestive of osseous metastasis from ILC.

Metastatic lobular carcinoma of breast mimics primary cervix carcinoma: two case reports and a review of the literature

Invasive lobular carcinoma (ILC) of the breast exhibits unusual clinicopathological, radiological, histological, and metastatic patterns. We present here two cases of ILC of the breast that presented with an unusual pattern of metastasis involving the uterus.

Our first patient presented to her primary gynaecologist with profuse vaginal bleeding and underwent total abdominal hysterectomy and bilateral salpingo-oophrectomy. She had fibroadenoma excised from her left breast four years previously. Histopathology revealed lobular carcinoma diffusely infiltrating uterus, cervix, and bilateral ovaries. Retrospective examination of the left breast showed induration along the previous fibroadenoma excision scar. A biopsy from the scar suggested lobular carcinoma.

Our second patient presented with a hard indurated cervix mass that mimicked primary cervix carcinoma. She had ILC of the right breast four years previously for which she underwent mastectomy followed by adjuvant chemotherapy and radiotherapy. She was on tamoxifen. Further evaluation at presentation with imaging showed extensive intra-abdominal disease involving peritoneum with moderate ascites, adnexal masses, and confluent para-aortic nodal mass. A cervix biopsy confirmed metastasis from lobular carcinoma.

Metastatic involvement of the genital tract should be considered in women with a history of breast cancer who present with abnormal vaginal bleeding, suspicious pelvic examination, or radiological findings. We suggest such patient be vigorously screened with biopsy even if the patient is disease-free for several years. It is crucial to differentiate the metastasis from primary carcinoma of the genital tract as there are vast differences in the management of each.

Comparison of 18F-FDG PET/CT for Systemic Staging of Newly Diagnosed Invasive Lobular Carcinoma Versus Invasive Ductal Carcinoma

Although guidelines such as those of the National Comprehensive Cancer Network consider (18)F-FDG PET/CT for systemic staging of newly diagnosed stage III breast cancer patients, factors in addition to stage may influence the utility of PET/CT. Because invasive lobular carcinoma (ILC) is less conspicuous than invasive ductal carcinoma (IDC) on (18)F-FDG PET, we hypothesized that tumor histology may be one such factor. We evaluated PET/CT systemic staging of patients newly diagnosed with ILC compared with IDC.

METHODS

In this Institutional Review Board-approved retrospective study, our Hospital Information System was screened for ILC patients who underwent PET/CT in 2006-2013 before systemic or radiation therapy. Initial stage was determined from examination, mammography, ultrasound, MR, or surgery. PET/CT was performed to identify unsuspected distant metastases. A sequential cohort of stage III IDC patients was evaluated for comparison. Upstaging rates were compared using the Pearson χ(2) test.

RESULTS

The study criteria were fulfilled by 146 ILC patients. PET/CT revealed unsuspected distant metastases in 12 (8%): 0 of 8 with initial stage I, 2 of 50 (4%) stage II, and 10 of 88 (11%) stage III. Upstaging to IV by PET/CT was confirmed by biopsy in all cases. Three of 12 upstaged patients were upstaged only by the CT component of the PET/CT, as the metastases were not (18)F-FDG-avid. In the comparison stage III IDC cohort, 22% (20/89) of patients were upstaged to IV by PET/CT. All 20 demonstrated (18)F-FDG-avid metastases. The relative risk of PET/CT revealing unsuspected distant metastases in stage III IDC patients was 1.98 times (95% confidence interval, 0.98-3.98) that of stage III ILC patients (P = 0.049). For (18)F-FDG-avid metastases, the relative risk of PET/CT revealing unsuspected (18)F-FDG-avid distant metastases in stage III IDC patients was 2.82 times (95% confidence interval, 1.26-6.34) that of stage III ILC patients (P = 0.007).

CONCLUSION

(18)F-FDG PET/CT was more likely to reveal unsuspected distant metastases in stage III IDC patients than in stage III ILC patients. In addition, some ILC patients were upstaged by non-(18)F-FDG-avid lesions visible only on the CT images. Overall, the impact of PET/CT on systemic staging may be lower for ILC patients than for IDC patients.

Appearance of untreated bone metastases from breast cancer on FDG PET/CT: importance of histologic subtype

PURPOSE

To determine if the histology of a breast malignancy influences the appearance of untreated osseous metastases on FDG PET/CT.

METHODS

This retrospective study was performed under IRB waiver. Our Hospital Information System was screened for breast cancer patients who presented with osseous metastases, who underwent FDG PET/CT prior to systemic therapy or radiotherapy from 2009 to 2012. Patients with invasive ductal carcinoma (IDC), invasive lobular carcinoma (ILC), or mixed ductal/lobular (MDL) histology were included. Patients with a history of other malignancies were excluded. PET/CT was evaluated, blinded to histology, to classify osseous metastases on a per-patient basis as sclerotic, lytic, mixed lytic/sclerotic, or occult on CT, and to record SUVmax for osseous metastases on PET.

RESULTS

Following screening, 95 patients who met the inclusion criteria (74 IDC, 13 ILC, and 8 MDL) were included. ILC osseous metastases were more commonly sclerotic and demonstrated lower SUVmax than IDC metastases. In all IDC and MDL patients with osseous metastases, at least one was FDG-avid. For ILC, all patients with lytic or mixed osseous metastases demonstrated at least one FDG-avid metastasis; however, in only three of seven patients were sclerotic osseous metastases apparent on FDG PET.

CONCLUSION

The histologic subtype of breast cancer affects the appearance of untreated osseous metastases on FDG PET/CT. In particular, non-FDG-avid sclerotic osseous metastases were more common in patients with ILC than in patients with IDC. Breast cancer histology should be considered when interpreting non-FDG-avid sclerotic osseous lesions on PET/CT, which may be more suspicious for metastases (rather than benign lesions) in patients with ILC.