Is staging breast magnetic resonance imaging for invasive lobular carcinoma worthwhile?

BACKGROUND: Invasive lobular carcinoma (ILC) is challenging to stage accurately using mammography (MG) and ultrasound (US) with undiagnosed ipsilateral and contralateral cancer resulting in poor patient outcomes including return to surgery. Our institution employs routine staging breast MRI in ILC for this reason. However, increased time for further imaging/biopsies contributes to patient anxiety and potentially delays definite management. We aimed to quantify the frequency of staging MRI-detected additional lesions requiring biopsy or follow-up, the added cancer detection rate and MRI prompted change in surgical management. METHODS: An observational study on staging breast MRI for newly diagnosed ILC at a tertiary Western Australian hospital from January 2019 to August 2022. Standardized 3T MRI protocol was performed, double read by unblinded fellowship-trained radiologists. Histopathology from biopsy, surgery, or first annual surveillance was the reference standard for additional MRI-detected lesions. RESULTS: One hundred ten MRI studies demonstrated 49 (45%) patients had at least one additional clinically significant MRI-detected lesion. Thirty-one patients had an additional ipsilateral lesion detected, of which 18 (58%) proved malignant; 14 (45%) multifocal and 4 (13%) multicentric ILC. Additional work-up of MRI-detected lesions averaged a 9-day delay to definitive surgery compared to patients with a negative or definitively benign MRI. MRI changed surgical planning in 11 of 110 cases from breast conservation surgery (BCS) to mastectomy and there were two contralateral cancers diagnosed. BCS reoperation rate was 11%. CONCLUSION: Staging MRI for ILC identifies clinically significant lesions in nearly half of patients, predominantly ipsilateral multifocal disease, without significant delay to definitive surgery.

Surveillance Strategies After Primary Treatment for Patients with Invasive Lobular Carcinoma of the Breast: Method of Local Recurrence Detection After Breast-Conserving Surgery.

BACKGROUND: Invasive lobular carcinoma (ILC) is the second most common subtype of breast cancer. Although mammography is known to have low sensitivity for ILC, there are no data to guide the optimal surveillance after treatment. We explored surveillance strategies after breast-conserving surgery (BCS) for ILC and determined the proportion of imaging-detected recurrences versus interval cancers. METHODS: From an institutional database of 813 women, we retrospectively identified patients who underwent BCS for stage I-III ILC and subsequently had a recurrence. We categorized patients by surveillance strategy and determined the modality of recurrence detection. Interval cancer rates for local recurrences were compared across surveillance strategies using the Chi-square test. We evaluated overall survival with the log-rank test and a Cox proportional hazards model. RESULTS: We included 58 patients with ILC who had a recurrence after BCS. Of these, 22 (37.9%) had local recurrence, 27 (46.6%) had distant recurrence, and 9 (15.5%) had both local and distant recurrence. Most patients underwent routine mammographic surveillance (65.2%), with 19.6% having supplemental breast magnetic resonance imaging (MRI) and 15.2% having no surveillance. The interval cancer rate was significantly higher in the mammographic surveillance group compared with the MRI surveillance group (61.9% vs. 16.7%; p < 0.001). CONCLUSION: In this study of patients with recurrence after BCS for primary treatment of stage I-III ILC, we found that most local recurrences were not detected by surveillance mammography. These data support further investigation of supplemental imaging beyond mammography specifically for patients with ILC who undergo BCS.

Gastric Signet Ring Cell Carcinoma Metastasis From Lobular Breast Cancer: A Diagnostic Pitfall.

Breast cancer is the most common type of cancer among women worldwide. Gastric metastasis from invasive lobular carcinoma of the breast is unusual. We report the case of a 66-year-old woman, under follow-up for an invasive classic lobular carcinoma of the left breast treated four years prior, who was admitted for upper abdominal discomfort and worsening constipation. Linitis plastica was suspected at gastroscopy. Histology of gastric biopsies showed a poorly cohesive carcinoma comprising signet ring cells, with no resemblance to the original breast cancer. An adequate immunochemistry panel, including estrogen receptor and GATA-3, eliminated primary gastric cancer and proved that the gastric lesion was a metastasis of the previously diagnosed invasive lobular breast cancer with additional signet ring cell differentiation, which is classified among its rare variants. This challenging case shows the importance of oncologic medical history and immunochemistry in differentiating between metastasis from invasive lobular breast carcinoma and primary gastric cancer. The distinction is necessary as the prognosis and approaches for treatment are different. When encountering a gastric signet ring cell carcinoma, one must keep in mind that it actually can be a metastasis from one of the several primary sites of origin.

Retrospective cohort study on the bilateral occurrence of invasive lobular breast cancer.

OBJECTIVE: Invasive lobular carcinoma (ILC) is the second most common histological subtype of invasive breast cancer, following the no special type (NST) invasive carcinoma. It has historically been assumed that ILC occurs bilaterally in 20-29 % of cases, which has influenced the inclusion of MRI in the standard workup of ILC according to European guidelines. However, challenging this long-held belief regarding the bilateral occurrence of ILC opens up the possibility of revising the guidelines and using MRI only for more specific indications. This study aims to evaluate whether the previously reported high percentage of bilaterality still holds true and to question the added value of MRI in the standard workup of ILC. STUDY DESIGN: A retrospective cohort study was conducted following approval from the institutional review board (EC 21/18/249) at Antwerp University Hospital (UZA). The cohort comprised female patients of all ages who had been diagnosed with either ILC or NST invasive carcinoma and had sought consultation at the UZA breast clinic. A comprehensive database was established to collect information on patient characteristics, imaging, and pathology. RESULTS: A total of 271 patients with ILC were included in the study, with incidence dates ranging from 01/01/2007 to 01/01/2023. Among these patients, a synchronous bilateral ILC lesion was observed in 1.85 % (5/271) of cases. This proportion is significantly lower than the reported percentage of patients with a bilateral lesion in the literature population, which stands at 4.95 %. The reference group consisted of 809 patients with NST invasive carcinoma, with incidence dates ranging from 01/01/2017 to 01/01/2023. In the control group, a synchronous bilateral NST lesion was observed in 3.96 % (32/809) of cases. There is no significant difference in the bilaterality rates between the group of ILC patients and the group of NST patients. Furthermore, MRI did not detect any histopathologically confirmed contralateral ILC lesion that had not already been detected by mammography or ultrasound. CONCLUSIONS: The study results indicate a lower occurrence of bilateral ILC than previously assumed. Additionally, the incidence of synchronous bilateral lesions in ILC patients is not higher compared to patients with NST invasive carcinoma. Performing an MRI does not provide additional value in detecting bilateral carcinomas in ILC. Consequently, it is recommended that the current European guidelines be reassessed, and the indications for undergoing an MRI should be adjusted accordingly.

Literature review on the bilateral occurrence of invasive lobular breast cancer.

Historically, it has been believed that invasive lobular carcinomas (ILC) occur more frequently bilaterally compared to other invasive subtypes, with estimates ranging between 20% and 29%. This study aims to determine if this historical perspective still holds true. A comprehensive literature review was conducted to examine the bilateral occurrence of lobular carcinoma using various imaging methods. Additionally, the role of magnetic resonance imaging (MRI) in detecting contralateral carcinomas was also investigated. A comprehensive search was conducted in the MedLine database on the PubMed platform, resulting in 307 articles published between January 1, 2014, and January 1, 2023. Various selection criteria were applied to identify articles relevant to the research question. After careful assessment, eight articles remained that met the eligibility criteria, all of which provided level-three evidence and were therefore included in the literature review. A total of 599 patients were included in this review, comprising a total of 602 cases of ILC. Six out of the eight articles reviewed provided information on the bilateral occurrence of ILC based on histopathology. A weighted average calculation yielded a bilaterality percentage of 4.95% (24 out of 485 cases). Four articles reported the number of bilateral cases identified through MRI, resulting in a weighted average of 10.2% (26 out of 255 cases). It is worth noting that 20.4% (100 out of 491) of the performed MRIs were found to be either useless or even harmful. Furthermore, MRI led to a change in the treatment plan in 27.7% (136 out of 491) of cases. Overall, it can be concluded that there is limited available data regarding the bilateral occurrence of ILC. The numbers found in the literature are also inconsistent and tend to vary. The literature review revealed a decrease in the percentage of bilaterality compared to historical beliefs. Based on this study, it can be concluded that a high number of MRI scans were found to be either useless or harmful. As a result of this conclusion and a higher sensitivity of other screening modalities, MRI may no longer be indicated as part of the standard workup for ILC. However, further research is necessary to validate these findings.

Deciphering the Clinical Behaviour of Invasive Lobular Carcinoma of the Breast Defines an Aggressive Subtype.

BACKGROUND: Invasive lobular carcinoma (ILC), the most common special type of breast cancer (BC), has unique clinical behaviour and is different from invasive ductal carcinoma of no special type (IDC-NST). However, ILC further comprises a diverse group of tumours with distinct features. This study aims to examine the clinicopathological and prognostic features of different variants of ILC, with a particular focus on characterising aggressive subtypes. METHODS: A large (n = 7140) well-characterised and histologically reviewed BC cohort with treatment and long-term follow-up data was investigated. The cohort was classified based on the WHO classification of tumours into main histological subtypes, including ILC and IDC-NST. ILCs were further classified into variants. Clinicopathological parameters and patient outcomes in terms of BC-specific survival (BCSS) and disease-free survival (DFS) were evaluated. RESULTS: ILC constituted 11% of the cohort. The most common non-classic ILC variants were pleomorphic (pILC) and solid (sILC), constituting 19% of ILC. Compared to classic and related variants (alveolar, trabecular, papillary, and tubulolobular; cILC), pILC and sILC variants were associated with aggressive tumour characteristics. The histologic grade of ILC was an important prognostic variable. The survival patterns identified an aggressive ILC subtype encompassing pILC and high-grade sILC. These tumours, which comprised 14% of the cases, were associated with clinicopathological characteristics of poor prognosis and had high BC-specific death and recurrence rates compared not only to cILC (p < 0.001) but also to IDC-NST (p = 0.02) patients. Contrasting this, cILC patients had significantly longer BCSS and DFS than IDC-NST patients in the first 10 to 15 years of follow-up. Adjuvant chemotherapy did not improve the outcome of patients with aggressive ILC subtypes. CONCLUSIONS: pILC and high-grade sILC variants comprise an aggressive ILC subtype associated with poor prognostic characteristics and a poor response to chemotherapy. These results warrant confirmation in randomised clinical trials.

Oncologic Safety of Immediate Oncoplastic Surgery Compared with Standard Breast-Conserving Surgery for Patients with Invasive Lobular Carcinoma.

BACKGROUND: Invasive lobular carcinoma (ILC) of the breast grows in a diffuse pattern, resulting in a high risk of positive margins at surgical resection. Oncoplastic approaches have been shown to reduce this risk, but concerns persist around the safety of immediate oncoplastic surgery for those with ILC. This study evaluated the short- and long-term oncologic outcomes of immediate oncoplastic surgery for patients with ILC. METHODS: This study retrospectively analyzed an institutional database of stages I to III ILC patients who underwent breast-conserving surgery (BCS) with or without immediate oncoplastic surgery (oncoplastic closure or oncoplastic reduction mammoplasty [ORM]). The study compared positive margin rates, rates of successful BCS, and recurrence-free survival (RFS) by type of surgery. RESULTS: For 494 patients the findings showed that the use of immediate ORM was associated with significantly lower odds of positive margins (odds ratio [OR], 0.34; 95 % confidence interval [CI], 0.17-0.66; p = 0.002). Both lumpectomy with oncoplastic closure and ORM were significantly associated with higher rates of successful BCS than standard lumpectomy (94.2 %, 87.8 %, and 73.9 %, respectively; p < 0.001). No difference in RFS was observed between those undergoing immediate oncoplastic surgery and those undergoing standard lumpectomy alone. CONCLUSIONS: The patients with stages I to III ILC who underwent immediate oncoplastic surgery had significant benefits including lower odds of positive margins and higher rates of successful BCS, with both types of immediate oncoplastic surgery showing similar RFS compared with lumpectomy alone. This supports the oncologic safety of immediate oncoplastic surgery for diffusely growing tumors such as ILC, providing it an ideal option for patients desiring BCS.

A Case Report of Invasive Lobular Carcinoma of Breast with Multiple Gastrointestinal and Cutaneous Metastases.

BACKGROUND: The metastasis of primary breast invasive lobular carcinoma to the gastrointestinal tract and skin is a rare phenomenon, with the simultaneous occurrence of both transfers being more uncommon. CASE PRESENTATION: This article reports a case of a patient with hormone receptor-positive, HER2-negative breast invasive lobular carcinoma with gastrointestinal tract and skin metastases. The patient was assessed by a second-look ultrasound and diagnosed by subsequent ultrasound-guided needle biopsy. Following endocrine therapy, a favorable effect was observed, with significant regression of the primary breast lesion, cutaneous metastases, and gastrointestinal metastases. CONCLUSION: Patients with breast invasive lobular carcinoma should be alert to the possibility of breast cancer metastasis, even if there are no obvious symptoms or signs, when they encounter rapidly progressive cutaneous nodules or plaques, or if they possess gastrointestinal abnormalities. For patients with negative breast ultrasonography for the first time, after combining mammography, Contrast-enhanced Spectral Mammography (CESM) or Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) examinations, if breast cancer is highly suspected, second-look ultrasound is particularly crucial at this juncture, which is the key prerequisite for breast needle biopsy and obtaining the gold standard of pathology.

Histological Patterns and Mammographic Presentation of Invasive Lobular Carcinoma Show No Obvious Associations.

Invasive lobular carcinoma of the breast has different mammographic appearances, including spiculated or lobulated masses, architectural distortion, increased breast density, and the possibility of also being occult. Histologically, the morphology is also variable, as several patterns have been described beside the classical one, including the solid, the alveolar, the trabecular, the one with tubular elements, and others. Of 146 ILC cases, 141 were reviewed for mammographic appearance and 136 for histological patterns by two radiologist and two pathologists, respectively; 132 common cases were analyzed for possible associations between mammographic presentation and the histological patterns. Interobserver agreement on the presence or absence of a given mammographic morphology ranged from 45% (increased density) to 95% (occult lesion); the most common radiomorphology was that of a spiculated mass. Interobserver agreement on the presence or absence of a given histological pattern ranged between 79% (solid) and 99% (classical) but was worse when semi-quantification was also included. The mammography-pathology correlation was less than optimal. Multifocality was more commonly detected by histology. The identification of a mammographic mass lesion often coincided with a mass-like lesion on the histological slides and vice versa, but nearly half of the mammographically occult lesions were felt to have masses on histological slides assessed grossly. Histological patterns showed no obvious associations with one or the other mammographic appearance.

Appendiceal Metastasis of Breast Cancer: A Case Report and a Literature Review.

Appendiceal metastases of breast cancer (BC) are very rare, and there are few reports of resection. Asymptomatic appendiceal enlargement is often suspected to be a primary appendiceal tumor, making it difficult to suspect metastatic tumors, especially metastases from BC. On the other hand, advances in drug therapy, including hormonal therapy for BC, have prolonged survival, and there is a possibility of encountering metastatic cases that have rarely been seen before. We herein present a case in which an enlarged appendix, identified during hormonal therapy for advanced BC, was laparoscopically removed and diagnosed as BC metastasis. A 53-year-old woman had been diagnosed with invasive ductal carcinoma (IDC) based on a breast biopsy, and the appendiceal specimen was diagnosed as invasive lobular carcinoma (ILC). We herein report this unique case and provide a detailed review of 13 previous reports.

Case report: Unusual breast cancer metastasis manifesting as a scalp lesion in a patient with invasive lobular carcinoma.

Breast cancer is the most prevalent cancer in women globally, often leading to distant metastasis in the lung, liver, or bones. Cutaneous metastasis represents an uncommon pattern in breast cancer, but when observed, it tends to manifest in the thorax and upper abdomen, primarily due to lymph node involvement. Therefore, occurrences of cutaneous metastasis on the scalp and extremities are infrequent. Moreover, invasive lobular carcinoma metastasizing to remote skin is rare among the breast cancer. This report presents a case of cutaneous metastasis of invasive lobular carcinoma to the scalp in a patient treated for breast cancer six years ago, with no signs of local recurrence or metastasis to other organs.

A case report of coexisting breast cancer with peritoneal, cutaneous tuberculosis, and potential Pott's disease: therapeutic and diagnostic challenges.

Introduction: Breast cancer affects one in eight women during their lifetime; it may coincide with other diseases due to its high prevalence. Different pathologies that occur simultaneously with breast cancer, or later during its course, lead to multiple interactions with cancer and have a significant impact on its management. Presentation of case: A 58-year-old Syrian female was admitted to our hospital for compliant of abdominal distension. Following complete examination, obtained biopsies confirmed the diagnosis of peritoneal tuberculosis. At a subsequent time, she suffered back pain and the computed tomography showed vertebral lesion with breast mass that was diagnosed as invasive lobular carcinoma (ILC) of the left breast. Vertebral lesion that appeared on radiologic assessment was diagnosed as cancer metastasis. However, the interaction of this metastasis with the proposed management diverted the attention towards its non-cancerous entity. Five months after completing the chemotherapy, biopsies revealed the recurrence of triple-negative (ER-, PR-, HER2- neu-) ILC of the breast. Ultimately, the patient was followed up for an overall duration of 4 years. Discussion: Latent tuberculosis infections may be activated by chemotherapy regimens that suppress immunity. Therefore, initial management of tuberculous infection is preferred when it coexists with cancer. Conclusion: Breast cancer is common and may co-present with other diseases, which, in some cases, produce mimicking lesions that alter its diagnosis. Pott's disease, albeit a rare entity, has shown a resurgence in developed countries and should be considered in the differential diagnosis of vertebral lesions in patients with breast cancer.

Metastasis to the bladder from primary breast cancer: A case report and literature review.

Breast cancer is the most prevalent malignant tumor affecting women and represents the leading cause of female cancer-related mortality worldwide. Although distant organ metastasis accounts for the majority of breast cancer-related deaths, reports on bladder metastasis are limited in the existing literature. The present study describes the case of a patient with bladder metastasis originating from breast cancer. In addition, the present study also provides a review of 54 cases of similar disease that have been documented in the currently available literature. The literature review aims to elucidate the clinicopathological characteristics and therapeutic approaches for such conditions. The median time from breast cancer diagnosis to bladder metastasis was found to be 5.6 years (range, 0-28 years). The origin of the bladder metastases was predominantly invasive ductal carcinoma (IDC) accounting for 52.3% of cases, followed by invasive lobular carcinoma, accounting for 40.9% of cases. The pathology in the primary tumor was the same as the pathology of the bladder metastases in all cases. There was an 88.9% concordance rate for estrogen receptor status, while the progesterone receptor status was 83.3% and the human epidermal growth factor receptor 2 expression status was 100%. The primary initial symptoms included urinary system manifestations, such as increased frequency, urgency, dysuria, urinary incontinence, nocturia and gross hematuria. For the cystoscopic examination, the predominant findings were bladder wall thickening or masses, along with ureteral orifice masses. Overall, the present study demonstrated that the occurrence of bladder metastasis often follows the metastasis of other organs, with IDC being the most prevalent subtype. The pathological characteristics between the primary tumor and bladder metastasis exhibit a high degree of concordance.

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.

Differences in Histological Subtypes of Invasive Lobular Breast Carcinoma According to Immunohistochemical Molecular Classification.

The technical complexity of gene expression profiling in routine practice has necessitated the use of surrogate molecular classification of breast cancer, based on immunohistochemical analyses. BACKGROUND AND OBJECTIVES: The aim of this study was to compare the differences between histological and molecular subtypes of invasive lobular carcinoma (ILC) of the breast, in order to be able to predict the behavior and prognosis of the disease, as well as to effectively determine therapy. MATERIAL AND METHODS: This study included 263 cases of breast ILC diagnosed over a seven-year period. The diagnosis of invasive lobular carcinoma is based on the characteristic growth pattern and phenotype of cancer cells with the respective subtypes: classic, alveolar, solid, tubulolobular, pleomorphic and mixed lobular type. The examined cases were divided into five groups according to molecular classification based on the expression of ER, PR, HER2 and Ki67 immunohistochemical markers. RESULTS: It was found that the pleomorphic subtype occurred statistically significantly less often as the luminal A subtype compared to others (p = 0.00027), and the HER2-enriched subtype occurred statistically significantly more often in the pT4 stage (p = 0.024). CONCLUSIONS: The results of this study significantly singled out the luminal A subtype, and among them classic ILC, as the subtype with the most favorable expression ratio of the investigated predictive/prognostic immunohistochemical markers.

Case report: Cutaneous metastases as a first manifestation from breast cancer with concurrent gastric metastases.

Background: Breast cancer represents a leading cause of malignancy among Chinese women, posing a significant health burden. The diagnosis of metastatic breast cancer, particularly to uncommon sites like the skin and stomach, presents distinct challenges. Case introduction: This case report describes a 71-year-old Chinese women with a persistent back rash lasting more than 6 months. Physical examination revealed red papules on her back. Immunohistochemistry confirmed positive for cytokeratin 7(CK7), GATA-3 and GCDFP15, as well as negative staining of cytokeratin 20 (CK20), suggesting breast cancer metastasis. Further evaluation revealed a breast nodule and axillary lymph node enlargement, with biopsies confirming invasive lobular carcinoma (ILC). Abdominal computed tomography (CT) revealed thickening of the gastric and ascending colon walls. Gastroscopy revealed chronic superficial atrophic gastritis. However, gastric metastasis was further confirmed by pathology. The patient initiated endocrine therapy with fulvestrant and exemestane, resulting in rash resolution and stable breast and stomach lesions after 3 months. Overall, the patient is experiencing an improvement in her condition and remains stable while continuing treatment. Conclusion: This case highlights the importance of considering atypical metastatic patterns in breast cancer and the potential efficacy of endocrine therapies in managing such cases. Moreover, it emphasizes the need for vigilance in breast cancer patients, especially those with ILC, as gastrointestinal symptoms may indicate gastric metastasis (GMs). Ultimately, early detection and appropriate treatment strategies, such as endocrine therapy, can contribute to improved outcomes in these challenging cases.

Is There a Special Role for Ovarian Hormones in the Pathogenesis of Lobular Carcinoma?

Lobular carcinoma represent the most common special histological subtype of breast cancer, with the majority classed as hormone receptor positive. Rates of invasive lobular carcinoma in postmenopausal women have been seen to increase globally, while other hormone receptor-positive breast cancers proportionally have not followed the same trend. This has been linked to exposure to exogenous ovarian hormones such as hormone replacement therapy. Reproductive factors resulting in increased lifetime exposure to endogenous ovarian hormones have also been linked to an increased risk of lobular breast cancer, and taken together, these data make a case for the role of ovarian hormones in the genesis and progression of the disease. In this review, we summarize current understanding of the epidemiological associations between ovarian hormones and lobular breast cancer and highlight mechanistic links that may underpin the etiology and biology.

Molecular and Clinical Portrait of HER2-low Invasive Lobular Carcinomas.

Invasive lobular carcinomas (ILCs) have a low frequency of ERBB2 amplification, therefore restricting the use of conventional anti-HER2 therapies for this histologic special type. Conversely, ILCs with low HER2 overexpression may represent a broader target for the use of emerging antibody drug conjugate therapies targeting HER2, since these treatments have proven effective in HER2-low breast cancers. Very scarce data about HER2-low ILCs have been so far published, although these tumors could have different prevalence and histomolecular specificities compared with invasive breast carcinoma of no special type (IBC-NST). Our aims in that context were to decipher the clinicopathological and molecular features of a large series of HER2-low ILCs. Comparative evaluation of HER2-low prevalence was done based on a retrospective series of 7970 patients from Institut Curie, with either primary invasive lobular (N = 1103) or no special type (N = 6867) invasive carcinoma. Clinicopathological and molecular analyses of HER2-zero, HER2-low, and HER2-positive ILCs were performed on a subgroup of 251 patients who underwent surgery for a primary ILC between 2005 and 2008. The mutational profile of these 251 cases was determined from RNAseq data. Compared with HER2-negative IBC-NSTs, the HER2-negative ILCs were found to display a higher frequency of HER2-zero cases (59.4% vs 53.7%) and a lower frequency of HER2-low (40.6% vs 46.3%) (P < .001). Clinicopathological features associated with HER2-low status (vs HER2-zero) in ILC were older age, postmenopausal status, nonclassic ILC histological types, higher grade, proliferation, and estrogen receptor expression levels. Survival curve analysis showed a significantly lower risk of local recurrence for HER2-low (vs HER2-zero) ILCs, but no association was found between HER2 status and either breast cancer-specific survival or distant metastasis-free interval. ERBB3 was the unique mutated gene exclusively associated with HER2-low ILCs yet being mutated at a low frequency (7.1%) (false discovery rate < 0.05). In conclusion, HER2-low ILCs exhibit their own particularities, both on clinical-pathological and molecular levels. Our findings call for larger multicenter validation studies.

Atypical Presentation of Breast Cancer Metastasis to the Bowel: A Case Report.

Breast cancer rarely metastasizes to the intestinal tract. It is even more uncommon to find intestinal metastasis as the first sign of distant spread. We describe an atypical case of small and large bowel carcinomas arising from primary breast cancer and presenting as the first evidence of distant metastasis. Clinicians should therefore consider the possibility of gastrointestinal (GI) metastasis when patients with breast cancer present with GI symptoms.

Metastatic profiles and survival differences between infiltrating ductal carcinoma and infiltrating lobular carcinoma in invasive breast cancer.

BACKGROUND: In this study, we conducted a comprehensive evaluation of metastatic profiles and survival outcomes in patients with infiltrating ductal carcinoma (IDC) and infiltrating lobular carcinoma (ILC) treated at our university hospital center. METHODS: We collected and analyzed data from all patients diagnosed with invasive breast cancer at our center between January 1, 2007, and 31 December 2014. We specifically compared three subgroups: patients with IDC, patients with ILC and patients with mixed carcinoma, which is a combination of IDC and ILC. RESULTS: Among the 1963 patients treated for invasive breast cancer in our center during the study period, 1435 had IDC, 466 had ILC, and 59 had mixed carcinoma. The incidence of patients with at least one positive axillary lymph node differed significantly: 40 % for IDC, 36 % for ILC, and 45 % for mixed carcinoma (p = 0.001). However, there was no significant difference in the mean number of positive nodes (p = 0.1633). The occurrence of distant metastases was lower in patients with ILC (p = 0.04), particularly in the case of brain metastases (p = 0.01), although there was no difference in bone or visceral metastatic sites. Patients with ILC exhibited a longer mean time to metastasis from the initial diagnosis of invasive breast carcinoma. Overall survival (p = 0.0525) and survival without locoregional recurrence (p = 0.026) were significantly different. Specifically, the 5-year overall survival rates for IDC, ILC, and mixed carcinoma were approximately 95 %. Distance metastatic-free survival at 5 years was 85 % for IDC, 91 % for ILC, and 87 % for mixed carcinoma (p = 0.00506). CONCLUSION: Our findings indicate variations in the distribution of distant metastatic sites among patients with IDC, ILC, and mixed carcinoma, as well as differences in survival outcomes. This study sheds light on the unique characteristics and clinical implications associated with these two distinct subtypes of invasive breast cancer.