Invasive Pleomorphic Lobular Carcinoma of the Breast: Pathologic, Clinical, and Therapeutic Considerations

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.

Comparison of Clinicopathological Features of Pleomorphic and Invasive Lobular Breast Carcinomas

PURPOSE

Accounting for about 15% of invasive lobular carcinomas and 1% of breast carcinomas, pleomorphic lobular carcinoma is known to be a rare histological subtype of invasive lobular carcinoma. Yet, it is more aggressive and produces a worse prognosis than other breast cancers. Ultimately, the present study compares the clinicopathological features of pleomorphic and invasive lobular breast carcinomas.

METHODS

In the study, we retrospectively evaluated the data of 262 patients with histological subtypes of classical and pleomorphic lobular cancers having been recruited for surgical operations. After resorting to Kolmogorov-Smirnov and Shapiro-Wilk tests to check the normality of distribution, the categorical and continuous variables were compared between the groups using the chi-square test and independent samples t test, respectively. In all analyses, we considered a P-value of <.05 to be statistically significant.

RESULTS

Our findings revealed that the groups with lobular and pleomorphic groups significantly differed by Ki-67 value, estrogen receptor negativity, grade, multicentricity, multifocality, surgical margin positivity, completion mastectomy, and metachronous contralateral tumor (P < .05).

CONCLUSION

We discovered that pleomorphic type was associated with higher grades, estrogen receptor negativity, and Ki-67 expression. The incidence of metachronous breast cancer was high in the pleomorphic group, which may be a noteworthy finding to be considered in follow-ups. In addition, the high rates of multicentricity and multifocality of tumors in the pleomorphic group may be associated with increased surgical margin positivity and a higher likelihood of mastectomy. In a nutshell, our findings may guide patients and surgeons regarding the type of intervention and reconstruction options to be adopted in prospective surgeries.

Exploration of cancer associated fibroblasts phenotypes in the tumor microenvironment of classical and pleomorphic Invasive Lobular Carcinoma

As the second most common subtype of breast carcinoma, Invasive Lobular Carcinoma (ILC) microenvironment features have not been thoroughly explored. ILC has different histological subtypes and elucidating differences in their microenvironments could lead to a comprehensive development of cancer therapies. We designed a custom-made cancer associated fibroblast (CAFs) panel and used multiplex immunofluorescence to identify the differences in tumor microenvironment between Classic ILC and Pleomorphic ILC.

Materials and methods

Multiplex immunofluorescence were performed on formalin fixed paraffin embedded tissues using Opal-7 color kit. The antibodies used for phenotyping CAFs were Pan CK (AE1/AE3), CD45, A-SMA, FAP, S100, Thy-1 with optimized dilutions. The images were acquired and analyzed using Vectra 3.0 imaging system and InForm software respectively.

Results

We studied 19 different CAFs colocalized phenotypes in the tumor, stroma and overall tissue compartments between classic and pleomorphic ILC. Total A-SMA+, A-SMA+FAP+S100+ and A-SMA+S100+ CAFs demonstrated higher densities in classic ILC cases while FAP+S100+ and S-100+ CAFs were increased in the pleomorphic subtype samples.

Conclusion

Our study explores multiple CAFs phenotypes between classical and pleomorphic ILC. We showed that CAFs subset differ between Classic ILC and Pleomorphic ILC. A-SMA CAFs are more prevalent in the TME of classic ILCs whereas Pleomorphic ILCs are dominated by CAFs without A-SMA expression. This also iterates the importance of exploring this particular type of breast carcinoma in more detail, paving the way for meaningful translational research.

Descriptive Study and Surgical Management Among Infiltrating Lobular Carcinoma Patients Admitted to King Abdulaziz Medical City From 2000 to 2017: A Retrospective Cross-Sectional Study

INTRODUCTION

Invasive lobular carcinoma (ILC) is the second most common histologic type of breast carcinoma. The etiology of ILC is unknown; however, many contributing risk factors have been suggested. Treatment of ILC can be divided into local and systemic. Our objectives were to assess the clinical presentations, risk factors, radiological findings, pathological types, and surgical options for patients with ILC treated at the national guard hospital. Identify the factors associated with metastasis and recurrence.

METHODS

Retrospective cross-sectional descriptive study at a tertiary care center in Riyadh. All adult patients aged 16 years and above, from different nationalities, and both genders, were diagnosed with ILC from 2000 to 2017 and followed up at KAMC. The sampling technique was a non-probability consecutive technique. Among 1066 patients identified, 91 patients were diagnosed with ILC over seventeen years study period.

RESULTS

The median age at the primary diagnosis was 50. On the clinical examination, 63 (71%) cases were found to have palpable masses which was the most suspicious finding. On radiology, the most encountered finding was speculated masses which were seen in 76 (84%). Regarding the pathology, unilateral breast cancer was seen in 82 while bilateral breast cancer was found only in eight. For the biopsy, a core needle biopsy was the most commonly used in 83 (91%) patients. The most documented surgery for ILC patients was a modified radical mastectomy. Metastasis in different organs was identified with the musculoskeletal system being the commonest site. Different significant variables were compared between patients with or without metastasis. Skin changes, post-operative invasion, estrogen, progesterone, and HER2 receptors were significantly associated with metastasis. Patients with metastasis were less likely to have conservative surgery. Regarding the Recurrence and five years survival, out of 62 cases, 10 had recurrence within five years, which was more prevalent in patients who had fine needle aspiration, excisional biopsy, and nulliparous patients.

CONCLUSION

To our knowledge, this is the first study to exclusively describe ILC in Saudi Arabia. The results of this current study are highly important, as these results provide baseline data of ILC in the capital city of Saudi Arabia.

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 Case Report on Apocrine Encapsulated Papillary Carcinoma of the Breast with Frank Invasion: A Diagnostic Quandary

Encapsulated papillary carcinoma is a special type of breast cancer defined in the fifth edition of the World Health Organization breast tumor classification guidelines. Apocrine encapsulated papillary carcinoma is extremely rare, and only 10 cases have been described previously. We encountered a case of apocrine encapsulated papillary carcinoma with frank invasion. The patient was a 77-year-old woman with a painless mass in her right breast. Core needle biopsy revealed that the tumor cells had voluminous eosinophilic cytoplasm and enlarged nuclei with prominent nucleoli. We diagnosed this lesion as carcinoma with apocrine differentiation and suggested the possibility of an encapsulated papillary carcinoma. The patient underwent a right-sided mastectomy. Gross examination of the resected specimen revealed a multilobulated tumor. Microscopically, the tumor cells, which had voluminous eosinophilic cytoplasm and enlarged nuclei with prominent nucleoli, proliferated in papillary fashion with fibrous stalks in the cystic space. Myoepithelial cells were not observed around the cystic space. Frank invasion was also observed around the encapsulated papillary carcinoma. Immunohistochemistry analysis revealed that the tumor cells were negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 and positive for androgen receptor and gross cys­tic disease fluid protein 15. Based on these findings, we diagnosed this lesion as an apocrine encapsulated papillary carcinoma with frank invasion.

Clinical outcomes in patients with triple negative or HER2 positive lobular breast cancer: a single institution experience

PURPOSE

Invasive lobular carcinomas (ILC) are characterised by loss of the cell adhesion molecule E-cadherin. Approximately 15% of ILC are ER negative at the time of breast cancer diagnosis, or at relapse due to loss of ER expression. Less than 5% of classical ILC but up to 35% of pleomorphic ILC are HER2 positive (HER2+).

METHODS

Retrospective analysis of clinic-pathological data from patients with Triple negative (TN) or HER2+ ILC diagnosed 2004-2014 at the Royal Marsden Hospital. The primary endpoint was median overall survival (OS) in patients with metastatic disease. Secondary endpoints included response rate to neo-adjuvant chemotherapy (NAC), median disease-free interval (DFI) and OS for patients with early disease.

RESULTS

Three of 16 patients with early TN ILC and 7/33 with early HER2+ ILC received NAC with pCR rates of 0/3 and 3/5 patients who underwent surgery, respectively. Median DFI was 28.5 months [95% Confidence interval (95%CI) 15-78.8] for TN ILC and not reached (NR) (111.2-NR) for HER2+ early ILC. Five-year OS was 52% (95%CI 23-74%) and 77% (95%CI 58-88%), respectively. Twenty-three patients with advanced TN ILC and 14 patients with advanced HER2+ ILC were identified. Median OS was 18.3 months (95%CI 13.0-32.8 months) and 30.4 months (95%CI 8.8-NR), respectively.

CONCLUSIONS

In our institution we report a high relapse rate after treatment for early TN ILC, but median OS from metastatic disease is similar to that expected from TN IDC. Outcomes for patients with advanced HER2+ ILC were less favourable than those expected for IDC, possibly reflecting incomplete exposure to anti-HER2 therapies.

CLINICAL TRIAL REGISTRATION

ROLo (ClinicalTrials.gov Identifier: NCT03620643), ROSALINE (ClinicalTrials.gov Identifier: NCT04551495).

The Rethinking Clinical Trials (REaCT) Program. A Canadian-Led Pragmatic Trials Program: Strategies for Integrating Knowledge Users into Trial Design

We reviewed patient and health care provider (HCP) surveys performed through the REaCT program. The REaCT team has performed 15 patient surveys (2298 respondents) and 13 HCP surveys (1033 respondents) that have addressed a broad range of topics in breast cancer management. Over time, the proportion of surveys distributed by paper/regular mail has fallen, with electronic distribution now the norm. For the patient surveys, the median duration of the surveys was 3 months (IQR 2.5-7 months) and the median response rate was 84% (IQR 80-91.7%). For the HCP surveys, the median survey duration was 3 months (IQR 1.75-4 months), and the median response rate, where available, was 28% (IQR 21.2-49%). The survey data have so far led to: 10 systematic reviews, 6 peer-reviewed grant applications and 19 clinical trials. Knowledge users should be an essential component of clinical research. The REaCT program has integrated surveys as a standard step of their trials process. The COVID-19 pandemic and reduced face-to-face interactions with patients in the clinic as well as the continued importance of social media highlight the need for alternative means of distributing and responding to surveys.

Triple-Positive Breast Carcinoma: Histopathologic Features and Response to Neoadjuvant Chemotherapy

CONTEXT.—

It is unclear whether HER2+ tumors expressing both estrogen receptor (ER) and progesterone receptor (PR), that is, triple-positive breast carcinomas (TPBCs), show unique morphologic and clinical features and response to neoadjuvant chemotherapy (NAC).

OBJECTIVE.—

To study the morphologic and immunohistochemical features of TPBCs from patients who underwent NAC.

DESIGN.—

We retrospectively reviewed core biopsy and post-NAC slides of 85 TPBCs. H-scores were calculated for ER and PR. HER2 slides and fluorescence in situ hybridization (FISH) reports were reviewed. Residual cancer burden was calculated for post-NAC specimens.

RESULTS.—

Eighty-one of the 85 tumors (95.3%) showed ductal histology, 3 (3.5%) were invasive lobular carcinomas, and 1 (1.2%) showed mixed ductal and lobular features. A subset showed mucinous (n = 7, 8.2%), apocrine (n = 5, 5.9%), and/or micropapillary (n = 4, 4.7%) differentiation. Fifty-four TPBCs (63.5%) showed high ER expression (H-score >200), including 27 (31.8%) with high expression of ER and PR. Fifty-two tumors (61.1%) showed HER2 3+ staining. Mean HER2/CEP17 ratio by FISH was 3.6 (range, 2-12.2) and mean HER2 signals per cell was 8 (range, 3.7-30.4). Pathologic complete response (pCR) rate was 35.3% (30 of 85). HER2 3+ staining was the only significant predictor of pCR on multivariate analysis (odds ratio = 9.215; 95% CI, 2.401-35.371; P < .001). The ER/PR expression did not correlate with response to therapy.

CONCLUSIONS.—

TPBCs are heterogeneous with some showing mucinous, lobular, or micropapillary differentiation. The pCR rate of TPBCs is similar to that reported for ER+/PR-/HER2+ tumors. HER2 overexpression by IHC was associated with significantly better response to therapy and may help select patients for treatment in the neoadjuvant setting.

Rare Breast Cancer Subtypes

PURPOSE OF REVIEW

Breast cancer is a collection of diseases including the more common invasive ductal and lobular carcinomas and rarer subtypes of breast cancer. This review summarizes the features of rare breast cancers.

RECENT FINDINGS

Each of the rare tumors has defined pathological and clinical features that impact treatment recommendations. In this review, we summarize these for each rare type of breast cancer and where available we include molecular features of each tumor. Rare subtypes of breast cancer each have unique features. In many cases, data is limited for the optimal treatment approaches.

Invasive pleomorphic lobular carcinoma of the breast with multiple metastases: A case report

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Invasive Pleomorphic Lobular Carcinoma(IPLC) accounts for less than 1% of breast cancer.

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This paper reports a case of IPLC with multiple metastases and gives review literature.

•

The patient’s general condition improved after our specific treatment options, which has a certain reference for the treatment of this kind of patients in the future.

Introduction and importance

IPLC (Invasive Pleomorphic Lobular Carcinoma) accounts for less than 1% of breast cancer. To the best of our knowledge, this is one of the few reported cases in the IPLC with multiple metastases. The patient's general condition got improved after our treatment, which has a certain reference for the treatment of this kind of patient in the future.

Case presentation

A 42-year-old female with IPLC and multiple metastases. The IPLC malignant cells were positive for p120 (cytoplasmic) and human epidermal growth factor receptor 2, negative for estrogen receptor, progesterone receptor, and E-cadherin. There were nodular enhancement foci in the liver, which are considered the metastatic lesions of the breast, and the liver function was abnormal. Multiple metastatic lesions of the vertebral body, appendage of the whole spine, and sternum. And C7, T1, and T9 vertebrae showed compression fractures.

Clinical discussion

IPLC has systemic metastasis which molecular typing by immunohistochemistry is HER-2 overexpression can choose chemotherapy combined with targeted therapy to prolong the survival time and improve the quality of life of patients. The patient was followed up.

Conclusions

This paper reports a case of IPLC with multiple metastases and gives review literature. Our treatment of the patient can be a reference for other clinicians.

Targetable alterations in invasive pleomorphic lobular carcinoma of the breast

Background

Invasive pleomorphic lobular carcinoma (PLC) of the breast is a subtype of invasive lobular cancer which compromises approximately 1% of all epithelial breast malignancies and is characterized by higher nuclear pleomorphism and poorer prognosis than classic invasive lobular cancer (ILC). Since PLC is more aggressive than classical ILC, we examined the underlying molecular alterations in this subtype of breast cancer to understand the possible benefit from targeted therapies.

Methods

In this study, we investigate the clinical characteristics and molecular alterations in 16 PLC from our institution. Additionally, we examined the clinical and genomic features in 31 PLC from the Cancer Genome Atlas (TCGA).

Results

Overall, our analysis of PLC found that 28% had activating ERBB2 mutations, 21% had ERBB2 amplification, and 49% activating PIK3CA mutations. Among cases from our institution, we found 19% with activating ERBB2 mutations, 25% had ERBB2 amplification, and 38% with activating PIK3CA mutations. In data from TCGA, 32% had activating ERBB2 mutations, 19% had ERBB2 amplification, and 55% had activating PIK3CA mutations. While classic ILC in TCGA had similar percentages of PIK3CA alterations compared to PLC, activating ERBB2 alterations were exceedingly rare, with no activating ERBB2 mutations and only one case with ERBB2 amplification. Interestingly, in further examining TCGA data which included FGFR1 and PTEN, 94% of PLC had alterations in ERBB2, FGFR1, or the PI3K pathway.

Conclusions

Our results show a high frequency of ERBB2 and PIK3CA alterations in PLC and suggest all PLC should be tested for potential therapeutic targeting.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-020-01385-5.

Clinicopathological and Molecular Characteristics of Pleomorphic Invasive Lobular Carcinoma

Pleomorphic invasive lobular carcinoma (PILC) is a distinct morphological and biologically aggressive variant of invasive lobular carcinoma (ILC). We hypothesized that was due to de novo activation of PI3K/Akt/mTOR pathway in PILC resulting in higher proliferation rate and markers of cell cycle activation. We identified PILC and ILC tumors and tested for PI3K/Akt/mTOR pathway activation by immunohistochemistry (PTEN and pS6K1) and gene expression analysis (by Nanostring nCounter system). Proliferation index (Ki67) was elevated in 85% of PILCs compared to 20% of ILCs (p < 0.007). PTEN expression was high in all while pS6K1 was high in 8/9 PILCs compared to 3/9 ILCs (p < 0.007). Gene expression analysis shows that PILCs have overexpression of genes involved in cell cycle proliferation, cellular proliferation, DNA damage, and repair genes but no difference in PI3K/Akt/mTOR pathway genes. PILCs are a biologically distinct group of ILC, and clinicopathological characteristics suggest they would have a more clinically aggressive behavior. In addition, our results indicate that PI3k/Akt/mTOR pathway and cell cycle proliferation are activated in majority of these tumors. Further studies are needed to investigate these mechanisms as there are approved therapies available that may benefit PILCs.

Case of HER2neu+ Invasive Pleomorphic Lobular Carcinoma With Response to Conventional Neoadjuvant Chemotherapy: A Viable Option for an Exceedingly Rare Breast Cancer Type

Invasive pleomorphic lobular carcinoma (IPLC) is an extremely rare form of breast cancer that accounts for less than 1% of all breast cancer cases. Due to this rarity, currently, there is a lack of an established standard of care for patients diagnosed with this form of breast cancer. In this case report, we present a 57-year-old female with a complex oncologic history diagnosed with clinical prognostic Stage IIA (ER 5%, PR 0%, HER2neu 3+) invasive pleomorphic lobular carcinoma of the left breast treated with neoadjuvant docetaxel, carboplatin, trastuzumab, and pertuzumab-based therapy (TCHP) followed by surgery. Surgical pathology revealed treatment-related changes with a definite response to neoadjuvant therapy. We report this case to highlight the response of this rare pathological entity to a standard neoadjuvant regimen such as docetaxel, carboplatin, trastuzumab, and pertuzumab.

Signet Ring Cell Differentiation in Salivary Duct Carcinoma with Rhabdoid Features: Report of Three Cases and Literature Review

Salivary duct carcinoma with rhabdoid features (SDCRF) is a rare salivary tumor with poor prognosis and is proposed as a salivary counterpart of pleomorphic lobular carcinoma of the breast (PLCB). Here, we report three cases of SDC with rhabdoid features (SDCRF) mimicking PLCB. Pleomorphic adenoma (PA) component was accompanied in all the cases confirming carcinoma ex PA. One patient had frequent rhabdoid features and showed invasive growth into the surrounding tissue. The other two patients had intracapsular tumor but with rhabdoid features. The patients with intracapsular SDCRF survived for > 5 years after surgery with no evidence of recurrence, whereas the patient with extracapsular SDCRF died 10 months after biopsy, and autopsy revealed disseminated metastasis to the central nervous system. Histologically, tumor cells in all three cases resembled PLCB, with a discohesive appearance, abundant cytoplasm, enlarged hyperchromatic nuclei, and similar immunohistochemical profiles, namely loss of membranous E-cadherin, obscured expression of membranous β-catenin, diffuse positivity of androgen receptor, gross cystic disease fluid protein-15, mitochondrial adenosine triphosphate synthase subunit β, MUC1, and INI-1. Estrogen and progesterone receptors were negative, and HER2 immunoreactivities were variable. The tumor cells of extracapsular invasive SDCRF exhibited higher MIB-1 labeling index and more frequent intracytoplasmic lumina than those of intracapsular SDCRF. Ultrastructurally, rhabdoid cells contained intracytoplasmic lumina with microvillous structure, analogous to those reported in PLCB. No intracytoplasmic intermediate filament aggregation was observed. These observations indicate that SDCRF is a salivary counterpart of PLCB and under signet ring cell differentiation.

Mitotic score and pleomorphic histology in invasive lobular carcinoma of the breast: impact on disease-free survival

PURPOSE

Pleomorphic invasive lobular carcinoma (ILC) has long been thought to have worse outcomes than classic ILC and is therefore often treated with chemotherapy. However, recent data question the utility of the pleomorphic designation, as the poor outcomes seen may be related to other associated high-risk features. Importantly, mitotic count may better define a subset of ILC with high risk of recurrence. We sought to determine the impact of pleomorphic histology versus mitotic count on disease-free survival (DFS) in pure ILC. Additionally, we evaluated whether pleomorphic histology was associated with receipt of chemotherapy when adjusting for other factors.

METHODS

We analyzed a cohort of 475 patients with stage I-III pure ILC. We used Kaplan-Meier estimates, and Cox proportional hazards and logistic regression for multivariate analyses. Pleomorphic histology was confirmed by central pathology review.

RESULTS

In a multivariate model, pleomorphic histology was not associated with reduced DFS. Only mitotic score, receptor subtype, and pathologic stage were independently and significantly associated with DFS. Patients with pleomorphic ILC were significantly more likely to receive chemotherapy than patients with classic ILC (adjusted odds ratio 2.96, p = 0.026).

CONCLUSIONS

The pleomorphic designation in ILC does not have clinical utility and should not be used to determine therapy. Rather, mitotic count identified clear prognostic groups in this cohort of pure ILC.

Invasive Pleomorphic-Type Lobular Carcinoma of the Breast Presenting as a Mucinous Carcinoma

Invasive mucinous carcinoma of the breast is mostly associated with invasive carcinoma of no special type (NST) and sometimes with neuroendocrine type tumors such as solid papillary carcinoma. Extracellular mucin production in invasive lobular carcinoma (ILC) is extremely rare. To the best of our knowledge only 18 such cases have been described in the literature. Here we present a unique case of invasive pleomorphic-type lobular carcinoma (IPTLC) presenting as a mucinous carcinoma of the breast on core needle biopsy. Here we discuss the impact and ways to suspect such case.

Outcomes of pleomorphic lobular carcinoma versus invasive lobular carcinoma

PURPOSE

Pleomorphic lobular carcinoma (PLC) is a rare histologic variant of invasive lobular carcinoma (ILC) that has been associated with worse clinical outcomes than classic ILC. Owing to its rarity, high-volume studies of its clinical characteristics and prognosis are lacking. The purpose of this study was to use a large, contemporary cancer database to investigate the clinical characteristics and survival outcomes for patients with PLC.

METHODS

The National Cancer Database (NCDB) was queried for women with cT1-4N1-3M0 breast cancer with either ILC or PLC histology having received definitive surgical therapy. Chi-squared analysis was performed to determine differences between the cohorts. Kaplan-Meier analysis evaluated overall survival (OS) between all patients and between patients when stratifying by age and subtype. Cox proportional hazards modeling determined variables associated with OS.

RESULTS

A total of 115,260 patients met the study criteria; of these, 114,859 (99.6%) had ILC, while 401 (0.4%) had PLC. A greater proportion of patients with PLC had T3-4 and node-positive disease, and were more likely to have ER- and HER2+ disease. PLC histology was associated with worse OS on both univariate and multivariate analysis (p < 0.001). PLC was associated with poorer OS in subgroups that were T3-4/N+ (but not T1-2N0) disease and ER+ (but not ER-) cancers, but not by HER2 status.

CONCLUSIONS

Patients with PLC, who were more likely to have ER- and HER2+ disease, experienced worse OS than patients with ILC, which may be limited to patients with more advanced clinical stage and ER + disease. Further work is needed to determine the optimal treatment for this more aggressive form of breast cancer.

A comparison of the imaging features of pleomorphic and classical invasive lobular carcinoma

PURPOSE

Pleomorphic invasive lobular carcinoma (pILC) is a distinct morphological variant of ILC with a poorer prognosis than classical ILC (cILC). The aim of this study was to ascertain whether the conventional imaging appearances of the two entities differ.

METHODS

A single-center retrospective review of conventional imaging was undertaken in 150 consecutive patients with histopathologically confirmed ILC (38 pILC; 112 cILC) between April 2010 and July 2015. Mammographic and sonographic findings were evaluated using the BI-RADS lexicon by a radiologist blinded to pathology, and the findings in the two groups were compared. The degree of discrepancy between imaging and pathological sizing in the two groups was evaluated.

RESULTS

Lesions were mammographically occult in 11% of pILC and 14% of cILC (p = 0.56). On mammography, skin or trabecular thickening and microcalcification were commoner in pILC than cILC (13% vs. 1%, p < 0.01; 25% vs. 5%, p < 0.01). Architectural distortion was more frequent in cILC than pILC (26% vs. 9%, p = 0.01). On ultrasound, pILC more frequently exhibited mixed echogenicity (28% vs. 13%; p = 0.04), skin thickening, subcutaneous or parenchymal edema (8% vs. 0%; p = 0.02), echogenic surrounding fat (33% vs. 9%; p < 0.01), and posterior acoustic enhancement (10% vs. 1%; p = 0.02) than cILC. CILC was more frequently manifested as a focal area of altered echogenicity (24% vs. 8%; p = 0.04). Mean elastography stiffness was higher for pILC (174.8 vs. 124.6 kPa; p = 0.02). Imaging-pathological size disparity was similar for both subtypes.

CONCLUSION

There are differences in the imaging features between pILC and cILC which reflect the more aggressive nature of pILC.

IRS2 mutations linked to invasion in pleomorphic invasive lobular carcinoma

Pleomorphic invasive lobular carcinoma (PILC) is an aggressive variant of invasive lobular breast cancer that is associated with poor clinical outcomes. Limited molecular data are available to explain the mechanistic basis for PILC behavior. To address this issue, targeted sequencing was performed to identify molecular alterations that define PILC. This sequencing analysis identified genes that distinguish PILC from classic ILC and invasive ductal carcinoma by the incidence of their genomic changes. In particular, insulin receptor substrate 2 (IRS2) is recurrently mutated in PILC, and pathway analysis reveals a role for the insulin receptor (IR)/insulin-like growth factor-1 receptor (IGF1R)/IRS2 signaling pathway in PILC. IRS2 mutations identified in PILC enhance invasion, revealing a role for this signaling adaptor in the aggressive nature of PILC.

Invasive Lobular Breast Carcinoma: Pleomorphic Versus Classical Subtype, Associations and Prognosis

BACKGROUND

Invasive pleomorphic lobular carcinoma (IPLC) has been associated with a worse prognosis compared with classic invasive lobular carcinoma (cILC); however, studies are small and conflicting. We seek to examine the prognosis of women with IPLC compared with cILC.

METHODS

A retrospective review of women with breast cancer at a single institution from 2003 to 2012 identified 193 women with invasive lobular carcinoma (ILC). IPLC was defined as ILC with a pathological description of primarily pleomorphic features and Nottingham histological grade score of 7, 8, or 9 or overall grade of 3 or mixed classic/pleomorphic features and overall grade of 3. All others were designated cILCs. Clinicopathologic variables, progression-free survival (PFS), per STEEP criteria, and overall survival (OS), using all-cause mortality, were examined in both groups.

RESULTS

Of the 193 women, 46 (24%) had IPLC and 147 (76%) had cILC. The IPLC group had significantly higher stage at diagnosis and more Hispanic women, but there were no differences in other clinicopathologic features or treatment. Median follow-up was 57 months (0.1-155 months). In univariate analysis, IPLC was associated with worse PFS (log-rank P = .09, Wilcoxon P = .01) but no significant differences in OS (log-rank P = .20, Wilcoxon P = .16). In multivariate models adjusting for stage, IPLC was not significantly associated with PFS (hazard ratio [HR] 1.43; 95% confidence interval [CI], 0.73-2.79; P = .30) or OS (HR 1.52; 95% CI, 0.58-4.01; P = .40).

CONCLUSIONS

IPLC was initially associated with worse PFS, but this was attenuated after adjustment for cancer stage, and there were no differences in OS.

Pancreatic metastasis from invasive pleomorphic lobular carcinoma of the breast: a rare case report

Background

Invasive pleomorphic lobular carcinoma (PLC) is an aggressive subtype of invasive lobular carcinoma of the breast, which has its own histopathological and biological features. The metastatic patterns for PLC are distinct from those of invasive ductal carcinoma. In addition, pancreatic metastasis from PLC is extremely rare.

Case presentation

We report a rare case of a 48-year-old woman presenting with clinical gastrointestinal symptoms and pancreatic metastasis of PLC. The pancreatic tumor was composed of pleomorphic tumor cells arranged in the form of solid sheets and nests and as single files, with frequent mitotic figures, nucleolar prominence, high nuclear to cytoplasmic ratio and loss of cohesion. The malignant cells were positive for p120 (cytoplasmic) and GATA3 and negative for estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, E-cadherin, gross cystic disease fluid protein 15 and mammaglobin, which indicated a lobular carcinoma phenotype of the breast.

Conclusions

To the best of our knowledge, this is one of the few reported cases in the literature of pancreatic metastasis of invasive lobular carcinoma of the breast, of which the definitive diagnosis was obtained only after surgery. Rare metastasis sites should be considered, particularly, when a patient has a medical history of PLC.

Strategies for obtaining bone biopsy specimens from breast cancer patients - Past experience and future directions

Background

Cancer and its treatment can have multiple effects on the bone. Despite the widespread use of in vivo and in vitro models, it is still necessary to understand these effects in humans. Obtaining human bone biopsies is technically challenging and in this article we review the experiences from the Ottawa Bone Oncology Program.

Methods

A series of bone biopsy studies in breast cancer patients with and without bone metastasis have been performed. We reviewed the results of these studies and present them in a descriptive manner. We discuss lessons learned from each project and how they have affected future directions for research.

Results

Since 2009, 5 studies have been performed accruing 97 breast cancer patients. Study endpoints have ranged from comparing the yield of malignant cells from CT-guided versus standard iliac crest biopsies, to studies assessing the feasibility of micro-CT analysis on Jedhadi trephines to evaluate bisphosphonate effects on bone micro-architecture. More recently, we have assessed the feasibility of performing repeat bone biopsies in the same patient as well as evaluating the practicality of obtaining bone tissue at the time of orthopaedic surgery.

Conclusion

Human bone tissue is an important biological resource. Our experience suggests that obtaining bone biopsies is feasible and can yield adequate amount of tumour cells for many studies. However, these remain technically challenging specimens to obtain and given the rapid advances in cancer therapeutics and the use of potent adjuvant bone-targeted agents, more centres need to be involved in these types of studies.

Linking DNA Damage and Hormone Signaling Pathways in Cancer

DNA damage response and repair (DDR) is a tightly controlled process that serves as a barrier to tumorigenesis. Consequently, DDR is frequently altered in human malignancy, and can be exploited for therapeutic gain either through molecularly targeted therapies or as a consequence of therapeutic agents that induce genotoxic stress. In select tumor types, steroid hormones and cognate receptors serve as major drivers of tumor development/progression, and as such are frequently targets of therapeutic intervention. Recent evidence suggests that the existence of crosstalk mechanisms linking the DDR machinery and hormone signaling pathways cooperate to influence both cancer progression and therapeutic response. These underlying mechanisms and their implications for cancer management will be discussed.