The utility of MYC and FLT4 in the diagnosis and treatment of postradiation atypical vascular lesion and angiosarcoma of the breast

MicroRNAs and angiosarcoma: are there promising reports?

In recent years, microRNAs (miRNAs) have garnered increasing attention for their potential implications in cancer pathogenesis, functioning either as oncogenes or tumor suppressors. Notably, angiosarcoma, along with various other cardiovascular tumors such as lipomas, rhabdomyomas, hemangiomas, and myxomas, has shown variations in the expression of specific miRNA subtypes. A substantial body of evidence underscores the pivotal involvement of miRNAs in the genesis of angiosarcoma and certain cardiovascular tumors. This review aims to delve into the current literature on miRNAs and their prospective applications in cardiovascular malignancies, with a specific focus on angiosarcoma. It comprehensively covers diagnostic methods, prognostic evaluations, and potential treatments while providing a recapitulation of angiosarcoma's risk factors and molecular pathogenesis, with an emphasis on the role of miRNAs. These insights can serve as the groundwork for designing randomized control trials, ultimately facilitating the translation of these findings into clinical applications. Moving forward, it is imperative for studies to thoroughly scrutinize the advantages and disadvantages of miRNAs compared to current diagnostic and prognostic approaches in angiosarcoma and other cardiovascular tumors. Closing these knowledge gaps will be crucial for harnessing the full potential of miRNAs in the realm of angiosarcoma and cardiovascular tumor research.

Establishment and characterization of the first patient-derived radiation-induced angiosarcoma xenograft model (RT-AS5)

Angiosarcomas are a heterogeneous group of rare endothelial malignancies with a complex, not completely unravelled biology. They encompass primary (sporadically occurring) angiosarcomas of several origins and secondary angiosarcomas, which often arise due to DNA damaging factors including radiotherapy or ultraviolet light exposure. The optimal treatment of metastatic angiosarcomas is unclear and the prognosis is poor. In order to discover novel treatment strategies for angiosarcomas it is important to take the heterogeneity of these tumors into account. For this reason it is also important to have preclinical models available for the different clinical subtypes. Owing to the rarity of angiosarcomas, models are scarce. So far, only five human cell lines of angiosarcomas (all of the scalp after UV exposure) are available worldwide. In this paper we describe a novel established patient-derived xenograft model of a radiotherapy-induced angiosarcoma of the breast. The tumor was characterized by a MYC amplification, CD31 and ERG immunohistochemical positivity and was further characterized by using next generation sequencing (TruSight Oncology 500) in combination with the R-package XenofilteR to separate mouse from human sequence reads.

Case report: Unique FLT4 variants associated with differential response to anlotinib in angiosarcoma

Angiosarcoma (AS) is a rare, clinically aggressive tumor with limited treatment options and a poor prognosis. Mutations involving the angiogenesis-related genesTP53, PTPRB, PLCG1, KDR as well as FLT4 amplification have been observed in AS. There is a potential therapeutic value of inhibition of the VEGF pathway against angiosarcoma. Our case first described a patient with two sites of cutaneous angiosarcomas (cASs) that responded differently to anlotinib. And genetic analysis revealed that those two sites had different FLT4 variants, suggesting that FLT4 amplification could be the cause of anlotinib non-response.

Primary breast angiosarcoma: A case report

Background

Primary breast angiosarcoma (PBA) is a rare sarcoma, accounting for only 0.04% of all breast malignancies, with a difficult diagnosis and a poor prognosis. Mastectomy is the standard treatment, and the role of adjuvant treatment (chemotherapy and/or radiotherapy following surgery) remains uncertain with very few studies.

Case Presentation

We report the case of a 17-year-old female patient who presented with a right breast lump that had rapidly increased in size and was hemorrhaging. She was diagnosed with breast angiosarcoma by needle biopsy and pathological evaluation. However, the mass showed a quick tendency to bleed during biopsies. After that, we performed angiography and tumor vascular embolization. The patient underwent a mastectomy followed by adjuvant chemotherapy.

Conclusion

Tumor vascular embolization reduced the surgical risk of PBA with hemorrhage complications. Postoperative therapeutic roles still need further exploration and verification.

Giant chondroid lipoma of the breast: A case report and literature review

Chondroid lipoma is a rare benign lesion affecting the breast, in which the diagnosis of malignancy is difficult to be excluded during preoperative studies. In this respect, a correct histopathological diagnosis is mandatory in order to avoid overdiagnosis and subsequently overtreatment. In the present study, the case of a 61-year-old patient who self-referred for the development of a large tumor at the level of the left breast is reported. Biopsy raised the suspicion of a chondroid lipoma; thus, the patient was submitted to conservative surgery. The lesion was completely excised by performing a total mastectomy. The histopathological studies confirmed the presence of chondroid lipoma, with no signs of malignant transformation. At the 24-month follow-up interval no signs of recurrence were detected. In conclusion, although it may reach significant dimensions, giant chondroid lipoma of the breast is a benign lesion that may benefit from conservative treatment and does not recur.

The impact of MYC amplification on clinicopathologic features and prognosis of radiation-associated angiosarcomas of the breast

AIMS

Radiation-associated angiosarcomas (RT-AS) of the breast are rare tumours with poor prognosis. MYC amplification is considered the hallmark of RT-AS and is sometimes used as a diagnostic tool to distinguish from other radiation-associated vascular lesions. However, a small subset of RT-AS lacks MYC amplification, which may be associated with better outcome. Loss of H3K27me3 expression by immunohistochemistry (IHC) has been recently postulated as an additional diagnostic marker for RT-AS. This study aimed to evaluate the impact of MYC amplification as detected by fluorescence in situ hybridization and/or next-generation sequencing on clinicopathologic features and outcome in a large cohort of RT-AS, compare outcome with radiation-associated sarcomas of the breast (RT-S) other than angiosarcoma, and evaluate expression of H3K27me3 IHC in these groups.

METHODS AND RESULTS

Eighty-one RT-AS were identified, including 73 MYC amplified and 8 (10%) non-amplified. MYC amplified RT-AS were diagnosed in older patients (median age 69 vs 61 years). The 5-year disease specific survival and overall survival were 56% and 47%, respectively. Older age, larger tumour size, positive margin and MYC amplification were associated with worse prognosis. None of the RT-AS showed complete loss of H3K27me3 IHC expression. All 18 RT-S were MYC non-amplified, and complete loss of H3K27me3 expression was seen in 2. We found no difference in prognosis between RT-AS and RT-S.

CONCLUSIONS

RT-AS is associated with a poor prognosis. Older age at diagnosis, larger tumour size, positive margin at excision and MYC amplification are associated with worse prognosis.

Primary Angiosarcoma of the Adrenal Gland: Report of 2 Cases and Review of the Literature

Primary adrenal angiosarcoma is a rare, malignant, vascular neoplasm. These neoplasms typically arise in middle age (median age of 60 years) and are more common in males (65%) than in females. Although rare, these neoplasms are aggressive with a propensity for local recurrence and metastasis and a median survival of 18 months. We present 2 cases of primary adrenal angiosarcoma with synchronous, ipsilateral adrenocortical adenomas. We review the cases of adrenal angiosarcoma reported since 1988 and discuss their clinical and histopathologic characteristics.

Genomic Characterization of Radiation-Induced Intracranial Undifferentiated Pleomorphic Sarcoma

Intracranial undifferentiated pleomorphic sarcoma remains a rare pathology within the sarcoma literature that may arise primarily or secondary after radiation therapy. Despite first-line treatment with maximal surgical resection, followed by nonstandardized adjuvant chemotherapy/radiation regimens, clinical prognosis remains exceedingly poor. Furthermore, there is a lack of genetic or molecular characterization to guide potential for targeted therapies. We present genomic analysis of a radiation-induced intracranial undifferentiated pleomorphic sarcoma in an 83-year-old woman with notable KIT and PDGFRA alterations. Further similar genomic studies of intracranial pleomorphic sarcoma are needed to develop better therapies for this rare but challenging disease entity.

Genomically Complex Human Angiosarcoma and Canine Hemangiosarcoma Establish Convergent Angiogenic Transcriptional Programs Driven by Novel Gene Fusions

Sporadic angiosarcomas are aggressive vascular sarcomas whose rarity and genomic complexity present significant obstacles in deciphering the pathogenic significance of individual genetic alterations. Numerous fusion genes have been identified across multiple types of cancers, but their existence and significance remain unclear in sporadic angiosarcomas. In this study, we leveraged RNA-sequencing data from 13 human angiosarcomas and 76 spontaneous canine hemangiosarcomas to identify fusion genes associated with spontaneous vascular malignancies. Ten novel protein-coding fusion genes, including TEX2-PECAM1 and ATP8A2-FLT1, were identified in seven of the 13 human tumors, with two tumors showing mutations of TP53. HRAS and NRAS mutations were found in angiosarcomas without fusions or TP53 mutations. We found 15 novel protein-coding fusion genes including MYO16-PTK2, GABRA3-FLT1, and AKT3-XPNPEP1 in 11 of the 76 canine hemangiosarcomas; these fusion genes were seen exclusively in tumors of the angiogenic molecular subtype that contained recurrent mutations in TP53, PIK3CA, PIK3R1, and NRAS. In particular, fusion genes and mutations of TP53 cooccurred in tumors with higher frequency than expected by random chance, and they enriched gene signatures predicting activation of angiogenic pathways. Comparative transcriptomic analysis of human angiosarcomas and canine hemangiosarcomas identified shared molecular signatures associated with activation of PI3K/AKT/mTOR pathways. Our data suggest that genome instability induced by TP53 mutations might create a predisposition for fusion events that may contribute to tumor progression by promoting selection and/or enhancing fitness through activation of convergent angiogenic pathways in this vascular malignancy. IMPLICATIONS: This study shows that, while drive events of malignant vasoformative tumors of humans and dogs include diverse mutations and stochastic rearrangements that create novel fusion genes, convergent transcriptional programs govern the highly conserved morphologic organization and biological behavior of these tumors in both species.

MYC gene amplification by fluorescence in situ hybridization and MYC protein expression by immunohistochemistry in the diagnosis of cutaneous angiosarcoma: Systematic review and appropriate use criteria

BACKGROUND

Secondary angiosarcoma (AS) most commonly follows breast cancer and includes postirradiation AS (PRAS) and lymphedema-associated AS. The frequent amplification of MYC (8q24.21) in secondary AS and the rising incidence of PRAS and atypical vascular lesions (AVLs) have prompted interest in the diagnostic and prognostic utility of MYC in AS.

METHODS

Retrospective series with ≥2 cases of cutaneous AS and describing the use of fluorescence in situ hybridization (FISH) for MYC amplification or immunohistochemistry (IHC) for MYC overexpression were included.

RESULTS

Sixteen studies met inclusion criteria. Overall, 93% of cases evaluated by FISH and IHC were concordant. The sensitivity of FISH in primary AS was only 6.8%, and protein overexpression occurred without amplification in sun-damaged skin. FISH and IHC were over 78% sensitive in secondary AS but negative in over 98% of AVLs. MYC amplification and FLT4 coamplification were associated with shorter overall survival in secondary AS.

CONCLUSION

FISH for MYC amplification and IHC for MYC overexpression are useful in distinguishing PRAS from AVLs and may also have prognostic value in secondary AS. In contrast, these methods have little diagnostic or prognostic value in primary AS and should not be used to distinguish primary AS from benign vascular neoplasms.

Primary mammary angiosarcomas harbor frequent mutations in KDR and PIK3CA and show evidence of distinct pathogenesis

Angiosarcoma (AS) is the most frequent primary sarcoma of the breast but nevertheless remains uncommon, accounting for <0.05% of breast malignancies. Secondary mammary AS arise following radiation therapy for breast cancer, in contrast to primary AS which occur sporadically. Essentially all show aggressive clinical behavior independent of histologic grade and most are treated by mastectomy. MYC amplification is frequently identified in radiation-induced AS but only rarely in primary mammary AS (PMAS). As a heterogeneous group, AS from various anatomic sites have been shown to harbor recurrent alterations in TP53, MAP kinase pathway genes, and genes involved in angiogenic signaling including KDR (VEGFR2) and PTPRB. In part due to its rarity, the pathogenesis of PMAS has not been fully characterized. In this study, we examined the clinical, pathologic, and genomic features of ten cases of PMAS, including one patient with bilateral disease. Recurrent genomic alterations were identified in KDR (70%), PIK3CA/PIK3R1 (70%), and PTPRB (30%), each at higher frequencies than reported in AS across all sites. Six tumors harbored a KDR p.T771R hotspot mutation, and all seven KDR-mutant cases showed evidence suggestive of biallelism (four with loss of heterozygosity and three with two aberrations). Of the seven tumors with PI3K alterations, six harbored pathogenic mutations other than in the canonical PIK3CA residues which are most frequent in breast cancer. Three AS were hypermutated (≥10 mutations/megabase (Mb)); hypermutation was seen concurrent with KDR or PIK3CA mutations. The patient with bilateral disease demonstrated shared alterations, indicative of contralateral metastasis. No MYC or TP53 aberrations were detected in this series. Immunohistochemistry for VEGFR2 was unable to discriminate between KDR-mutant tumors and benign vascular lesions of the breast. These findings highlight the underrecognized frequency of KDR and PIK3CA mutation in PMAS, and a significant subset with hypermutation, suggesting a pathogenesis distinct from other AS.

Sequential molecular and cytologic analyses provides a complementary approach to the diagnosis of pancreatic cystic lesions: a decade of clinical practice

INTRODUCTION

Many pancreatic cystic lesions (PCL) are of neoplastic nature with potential to progress to pancreatic adenocarcinoma. Early stratification of patients to either clinical observation or surgical intervention can considerably increase the survival rate. Recent studies have shown the value of molecular analysis to current diagnostic modalities.The aim of this study is to evaluate the diagnostic improvement by utilizing multiple sequential cytologic and molecular cyst fluid analyses.

MATERIALS AND METHODS

We prospectively evaluated 58 patients for whom multiple endoscopic ultrasound-guided fine-needle aspiration of cyst fluid specimens were available. Specimens were subjected to next generation sequencing to identify any recurrent gene mutations commonly found in PCL. The molecular findings were compared with cytologic and final diagnoses.

RESULTS

Cytologic diagnoses were classified into 3 groups: non-diagnostic (first visit: 33.9%, cumulative: 15.8%, P = 0.03), negative (1st visit: 53.6%, cumulative: 56.1%, P = 0.85) and atypical/suspicious/positive (first visit: 12.5%, cumulative: 28.1%, P = 0.06). The mutational analyses were clustered into indeterminate/failure (first visit: 1.7%, cumulative: 0%), KRAS/GNAS/VHL group (first visit: 50.0%, cumulative: 53.4%) and any mutation (first visit: 50.0%, cumulative: 53.4%). Mutational analysis identifies up to 72% and 71% whereas cytologic analysis classified up to 46% and 63% of lesions correctly in first and multiple visits, respectively.

CONCLUSIONS

The cytology and molecular analyses provide a complementary approach to patients with PCL. Power of molecular analysis in detection of a neoplastic lesion is significantly higher in one visit (P = 0.01) with comparable detection rates (P = 0.43) for both cytologic and molecular analyses after multiple visits.

Prediction for Intravenous Immunoglobulin Resistance Combining Genetic Risk Loci Identified From Next Generation Sequencing and Laboratory Data in Kawasaki Disease

Background: Kawasaki disease (KD) is the most common cause of acquired heart disease. A proportion of patients were resistant to intravenous immunoglobulin (IVIG), the primary treatment of KD, and the mechanism of IVIG resistance remains unclear. The accuracy of current models predictive of IVIG resistance is insufficient and doesn't meet the clinical expectations. Objectives: To develop a scoring model predicting IVIG resistance of patients with KD. Methods: We recruited 330 KD patients (50 IVIG non-responders, 280 IVIG responders) and 105 healthy children to explore the susceptibility loci of IVIG resistance in Kawasaki disease. A next generation sequencing technology that focused on 4 immune-related pathways and 472 single nucleotide polymorphisms (SNPs) was performed. An R package SNPassoc was used to identify the risk loci, and student's t-test was used to identify risk factors associated with IVIG resistance. A random forest-based scoring model of IVIG resistance was built based on the identified specific SNP loci with the laboratory data. Results: A total of 544 significant risk loci were found associated with IVIG resistance, including 27 previous published SNPs. Laboratory test variables, including erythrocyte sedimentation rate (ESR), platelet (PLT), and C reactive protein, were found significantly different between IVIG responders and non-responders. A scoring model was built using the top 9 SNPs and clinical features achieving an area under the ROC curve of 0.974. Conclusions: It is the first study that focused on immune system in KD using high-throughput sequencing technology. Our findings provided a prediction of the IVIG resistance by integrating the genotype and clinical variables. It also suggested a new perspective on the pathogenesis of IVIG resistance.

Somatic molecular analysis augments cytologic evaluation of pancreatic cyst fluids as a diagnostic tool

Objective: Better tools are needed for early diagnosis and classification of pancreatic cystic lesions (PCL) to trigger intervention before neoplastic precursor lesions progress to adenocarcinoma. We evaluated the capacity of molecular analysis to improve the accuracy of cytologic diagnosis for PCL with an emphasis on non-diagnostic/negative specimens. Design: In a span of 7 years, at a tertiary care hospital, 318 PCL endoscopic ultrasound-guided fine needle aspirations (EUS-FNA) were evaluated by cytologic examination and molecular analysis. Mucinous PCL were identified based on a clinical algorithm and 46 surgical resections were used to verify this approach. The mutation allele frequency (MAF) of commonly altered genes (BRAF, CDKN2A, CTNNB1, GNAS, RAS, PIK3CA, PTEN, SMAD4, TP53 and VHL) was evaluated for their ability to identify and grade mucinous PCL. Results: Cytology showed a diagnostic sensitivity of 43.5% for mucinous PCL due in part to the impact of non-diagnostic (28.8%) and negative (50.5%) specimens. Incorporating an algorithmic approach or molecular analysis markedly increased the accuracy of cytologic evaluation. Detection of mucinous PCL by molecular analysis was 93.3% based on the detection of KRAS and/or GNAS gene mutations (p = 0.0001). Additional genes provided a marginal improvement in sensitivity but were associated with cyst type (e.g. VHL) and grade (e.g. SMAD4). In the surgical cohort, molecular analysis and the proposed algorithm showed comparable sensitivity (88.9% vs. 100%). Conclusions: Incorporating somatic molecular analysis in the cytologic evaluation of EUS-FNA increases diagnostic accuracy for detection, classification and grading of PCL. This approach has the potential to improve patient management.

Bioinformatics analyses of significant genes, related pathways and candidate prognostic biomarkers in glioblastoma

Glioblastoma (GBM) is the most common type of malignant tumor of the central nervous system. The prognosis of patients with GBM is very poor, with a survival time of ~15 months. GBM is highly heterogeneous and highly aggressive. Surgical removal of intracranial tumors does provide a good advantage for patients as there is a high rate of recurrence. The understanding of this type of cancer needs to be strengthened, and the aim of the present study was to identify gene signatures present in GBM and uncover their potential mechanisms. The gene expression profiles of GSE15824 and GSE51062 were downloaded from the Gene Expression Omnibus database. Normalization of the data from primary GBM samples and normal samples in the two databases was conducted using R software. Then, joint analysis of the data was performed. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed, and the protein‑protein interaction (PPI) network of the differentially expressed genes (DEGs) was constructed using Cytoscape software. Identification of prognostic biomarkers was conducted using UALCAN. In total, 9,341 DEGs were identified in the GBM samples, including 9,175 upregulated genes and 166 downregulated genes. The top 1,000 upregulated DEGs and all of the downregulated DEGs were selected for GO, KEGG and prognostic biomarker analyses. The GO results showed that the upregulated DEGs were significantly enriched in biological processes (BP), including immune response, cell division and cell proliferation, and the downregulated DEGs were also significantly enriched in BP, including cell growth, intracellular signal transduction and signal transduction by protein phosphorylation. KEGG pathway analysis showed that the upregulated DEGs were enriched in circadian entrainment, cytokine‑cytokine receptor interaction and maturity onset diabetes of the young, while the downregulated DEGs were enriched in the TGF‑β signaling pathway, MAPK signaling pathway and pathways in cancer. All of the downregulated genes and the top 1,000 upregulated genes were selected to establish the PPI network, and the sub‑networks revealed that these genes were involved in significant pathways, including olfactory transduction, neuroactive ligand‑receptor interaction and viral carcinogenesis. In total, seven genes were identified as good prognostic biomarkers. In conclusion, the identified DEGs and hub genes contribute to the understanding of the molecular mechanisms underlying the development of GBM and they may be used as diagnostic and prognostic biomarkers and molecular targets for the treatment of patients with GBM in the future.

Survivin: A novel marker and potential therapeutic target for human angiosarcoma

Human angiosarcoma is a rare malignant vascular tumor associated with extremely poor clinical outcome and generally arising in skin of the head and neck region. However, little is known about the molecular pathogeneses and useful immunohistochemical markers of angiosarcoma. To investigate the mechanisms of angiosarcoma progression, we collected 85 cases of human angiosarcoma specimens with clinical records and analyzed ISO-HAS-B patient-derived angiosarcoma cells. As control subjects, 54 cases of hemangioma and 34 of pyogenic granuloma were collected. Remarkably, consistent with our recent observations regarding the involvement of survivin expression following Hippo pathway inactivation in the neoplastic proliferation of murine hemangioendothelioma cells and human infantile hemangioma, nuclear survivin expression was observed in all cases of angiosarcoma but not in hemangiomas and pyogenic granulomas, and the Hippo pathway was inactivated in 90.3% of yes-associated protein (YAP) -positive angiosarcoma cases. However, survivin expression modes and YAP localization (Hippo pathway activation modes) were not correlated with survival. In addition, we confirmed that survivin small interference RNA (siRNA) transfection and YM155, an anti-survivin drug, elicited decreased nuclear survivin expression and cell proliferation in ISO-HAS-B cells which expressed survivin consistently. Conclusively, these findings support the importance of survivin as a good marker and critical regulator of cellular proliferation for human angiosarcoma and YM155 as a potential therapeutic agent.

Pleural epithelioid angiosarcoma with lymphatic differentiation arisen after radiometabolic therapy for thyroid carcinoma: immunohistochemical findings and review of the literature

Background

Pleural angiosarcoma is a rare tumor that causes diffuse pleural thickening and effusion, mimicking mesothelioma. Immunohistochemistry is needed to highlight endothelial differentiation. We describe the first case of pleural angiosarcoma with lymphatic differentiation following radiometabolic therapy for thyroid carcinoma.

Case presentation

A 50-year-old man showed diffuse pleural thickening and effusion. Nine years earlier, he underwent thyroidectomy and radiometabolic therapy for thyroid carcinoma with lymph node metastases. Histologically, the tumor consisted of a solid proliferation of atypical epithelioid cells and anastomosed vascular spaces, lacking of red blood cells and containing Alcian blue positive material. The tumor showed positive immunostaining for Vimentin, CD31, CK7, D2–40, c-MYC, Ki67, focal positivity for PanCK, and negative immunostaining for Factor VIII, CD34, WT1, CK5/6, Calretinin, EMA, HBME-1, CEA, p63, EpCAM, Bcl-2, TTF1 and Thyroglobulin. CD99 showed a granular/paranuclear pattern of positivity. The histological and immunohistochemical features were consistent with “pleural angiosarcoma with lymphatic differentiation, epithelioid variant”.

Discussion and conclusions

Epithelioid angiosarcoma with lymphatic differentiation is very rare and aggressive. Moreover, the positivity for c-MYC suggests the relationship with radiometabolic therapy. To our knowledge, this is the first case of pleural c-MYC-positive angiosarcoma with lymphatic differentiation reported in the literature and the first one arisen after radiometabolic therapy for thyroid carcinoma.

Core Biopsy of Vascular Neoplasms of the Breast: Pathologic Features, Imaging, and Clinical Findings

Vascular lesions (VLs) of the breast present a diagnostic challenge on breast core biopsy (BCBx). We report on 27 VLs presenting on BCBx. The mean patient age was 60 years, and mean size was 7.5 mm (range, 1.6 to 16 mm). Presentation included palpable mass in 6 (22%), incidental in 6 (22%), and an imaging abnormality in 15 (56%) cases. Imaging impression included hematoma (24%), lymph node (10%), fat necrosis (10%), tortuous vessel (5%), and not provided in 52%. The lesions were classified on the basis of BCBx or BCBx and excision (available in 16 pts) as follows: 1 low-grade angiosarcoma, 8 angiolipomas, 6 capillary hemangiomas, 4 cavernous hemangiomas, 2 hemangiomas (not otherwise specified), 1 papillary endothelial hyperplasia, and 5 perilobular hemangiomas. The angiosarcoma was 9 mm, detected incidentally by magnetic resonance imaging, and showed dissection of stromal collagen, infiltration of glands, high cellularity, moderate cytologic atypia, scant mitotic activity, and Ki-67 reactivity of 10%. Among the 26 benign VLs, worrisome histologic features were noted in 14 on BCBx, including anastomosing vascular channels in 9, moderate cytologic atypia in 4, high cellularity in 2, Ki-67>10% in 2, mitotic activity in 1, and infiltration of glands in 1. Of the 12 VLs without worrisome features, the lesion extended to edge of core in 8, precluding complete evaluation. BCBx of VLs presents diagnostic challenges due to overlapping clinicopathologic and radiologic features with low-grade angiosarcoma. If completeness of removal is documented on BCBx, and cytoarchitectural changes are not worrisome, follow-up could be considered rather than excision. However, only 4 of these cases fulfilled those criteria.

Vascular lesions of the breast

Vascular lesions of the breast comprise a heterogeneous group that includes a variety of benign, atypical, and malignant lesions. The presentation of these lesions ranges from those that are microscopic and discovered incidentally, to large tumors that may extensively involve the breast parenchyma and skin. In addition, some non-vascular breast lesions have features that may mimic those of vascular lesions and need to be distinguished from them in order to avoid an erroneous diagnosis. In this review, we discuss the spectrum of vascular lesions of the breast with particular emphasis on those lesions of greatest clinical importance, angiosarcoma and atypical vascular lesions. We also discuss lesions that may be mistaken for vascular lesions.

Vascular tumours of the breast: a comprehensive review with focus on diagnostic challenges encountered in the core biopsy setting

Vascular proliferations of the breast comprise a spectrum of benign and malignant lesions. In limited samples, such as core needle biopsies (CNB), these lesions may be difficult to distinguish due to significant overlap in morphological features. As the treatment and prognosis of these entities vary widely, it is important for pathologists to consider a complete differential diagnosis and correctly synthesise histological features, results of adjunctive immunohistochemical studies, and pertinent clinical and imaging information, to render an accurate diagnosis in such limited samples. The diagnostic pitfalls of under- or overdiagnosis of vascular lesions sampled in CNB will also be discussed.

Modern therapies and iatrogenic changes in breast pathology

Iatrogenic changes within the breast can provide challenges for the histopathologist in routine practice. Diagnostic procedures, such as core biopsies, result in reactive changes and can cause displacement of benign and malignant cells, the interpretation of which may cause difficulties in the resection specimen. Breast augmentation surgery with implants or injection of fillers, performed for cosmetic reasons or as part of a reconstructive process following removal of breast cancer, also produces reactive changes locally and at distant sites that may mimic cancer. The entity of implant-associated anaplastic large-cell lymphoma is now well recognized, with progress in our understanding of the underlying biological factors that drive its development. Chemotherapy and radiotherapy used in the treatment of breast cancer causes characteristic changes in normal breast tissue, and can alter the histological appearance and receptor status of the tumour. Radiotherapy to the breast, for breast cancer or childhood malignancies, increases the risk of developing a secondary malignancy in the breast long after treatment. In this review, we describe some of the iatrogenic changes that may be seen in histological specimens from the breast.

Targeted massively parallel sequencing of angiosarcomas reveals frequent activation of the mitogen activated protein kinase pathway

Angiosarcomas are rare malignant mesenchymal tumors of endothelial differentiation. The clinical behavior is usually aggressive and the prognosis for patients with advanced disease is poor with no effective therapies. The genetic bases of these tumors have been partially revealed in recent studies reporting genetic alterations such as amplifications of MYC (primarily in radiation-associated angiosarcomas), inactivating mutations in PTPRB and R707Q hotspot mutations of PLCG1. Here, we performed a comprehensive genomic analysis of 34 angiosarcomas using a clinically-approved, hybridization-based targeted next-generation sequencing assay for 341 well-established oncogenes and tumor suppressor genes. Over half of the angiosarcomas (n = 18, 53%) harbored genetic alterations affecting the MAPK pathway, involving mutations in KRAS, HRAS, NRAS, BRAF, MAPK1 and NF1, or amplifications in MAPK1/CRKL, CRAF or BRAF. The most frequently detected genetic aberrations were mutations in TP53 in 12 tumors(35%) and losses of CDKN2A in9 tumors (26%). MYC amplifications were generally mutually exclusive of TP53 alterations and CDKN2A loss and were identified in 8 tumors (24%), most of which (n = 7, 88%) arose post-irradiation. Previously reported mutations in PTPRB (n = 10, 29%) and one (3%) PLCG1 R707Q mutation were also identified. Our results demonstrate that angiosarcomas are a genetically heterogeneous group of tumors, harboring a wide range of genetic alterations. The high frequency of genetic events affecting the MAPK pathway suggests that targeted therapies inhibiting MAPK signaling may be promising therapeutic avenues in patients with advanced angiosarcomas.

MYC immunohistochemistry in angiosarcoma and atypical vascular lesions: practical considerations based on a single institutional experience

Angiosarcoma (AS) is an uncommon vascular malignancy with an aggressive clinical course. Radiation-associated angiosarcoma (RAAS) and Stewart-Treves syndrome are associated with MYC gene amplification and protein overexpression, while other radiation-associated vascular lesions including atypical vascular lesions (AVL) are not associated with MYC overexpression. In contrast, de novo AS represent a group of molecularly heterogeneous tumours, for which MYC expression has not been extensively examined. In this study, MYC immunohistochemistry (IHC) was performed on representative whole tissue sections of a large retrospective cohort of de novo AS, RAAS, Stewart-Treves syndrome, and AVL and evaluated using a semi-quantitative scoring method. MYC is strongly expressed in the majority of RAAS and Stewart-Treves syndrome. De novo AS demonstrate variable MYC expression, with high-grade tumours showing significantly higher MYC expression than low-grade tumours. In contrast, MYC expression in AVL is predominantly negative but may occasionally show focal staining. These results indicate that unequivocal strong MYC IHC staining supports the diagnosis of RAAS. In rare cases of RAAS without strong MYC expression, however, particularly relatively low-grade tumours for which the differential diagnosis includes AVL, the distinction between these lesions should be made on morphological grounds using previously established criteria (i.e., significant atypia, deep invasion, infiltrative growth, etc.). Increased MYC expression in high-grade de novo AS suggests that MYC overexpression may play a role in the pathogenesis of these tumours, and MYC IHC may be a prognostic and/or therapeutic biomarker in a subset of these tumours.

Recurrent CIC Gene Abnormalities in Angiosarcomas: A Molecular Study of 120 Cases With Concurrent Investigation of PLCG1, KDR, MYC, and FLT4 Gene Alterations

Angiosarcoma (AS) is a rare sarcoma subtype showing considerable clinicopathologic and genetic heterogeneity. Most radiation-induced AS show MYC gene amplifications, with a subset of cases harboring KDR, PTPRB, and PLCG1 mutations. Despite recent advances, the genetic abnormalities of most primary AS remain undefined. Whole-transcriptome sequencing was initiated in 2 index cases of primary soft tissue AS with epithelioid morphology occurring in young adults for novel gene discovery. The candidate abnormalities were validated and then screened by targeted sequencing and fluorescence in situ hybridization in a large cohort of 120 well-characterized AS cases. Findings were subsequently correlated with the status of KDR, PLCG1, MYC, and FLT4 gene abnormalities. The clinicopathologic relevance and prognostic significance of these genetic changes were analyzed by statistical methods. Concurrent CIC mutations and CIC rearrangements were identified in both index cases, with a CIC-LEUTX fusion detected in 1 case. Upon screening, an additional visceral AS in a young adult had a complex CIC rearrangement, whereas 6 others harbored only CIC mutations. All 3 CIC-rearranged AS cases lacked vasoformation and had a solid growth of round, epithelioid to rhabdoid cells, showing immunoreactivity for CD31 and Ets-related gene and sharing a transcriptional signature with other round cell sarcomas, including CIC-rearranged tumors. Overall, CIC abnormalities occurred in 9% (9/98) of cases, affecting younger patients with primary AS, with an inferior disease-free survival. In contrast, PLCG1 and KDR mutations occurred in both primary and secondary AS cases, accounting for 9.5% and 7%, respectively, with a predilection for breast and bone/viscera location, regardless of MYC status. MYC amplification was present in most secondary AS related to breast cancer (91%) compared with other causes (25%) or primary AS (7%). FLT4-amplified AS lacked PLCG1/KDR mutations, occurring predominantly in MYC-amplified population, and showed poor prognosis.

Radiation-Induced Breast Angiosarcoma: Case Report and Clinical Approach

IMPORTANCE

Radiation-induced angiosarcoma after conservative treatment of breast cancer affects a small percentage of patients but has a significant impact on survival. Early detection requires a high index of suspicion and is important for optimal management of this aggressive disease.

OBSERVATIONS

The patient reported here presented with radiation-induced angiosarcoma of the left breast 14 years after radiation therapy. Histopathology was positive for anti-CD31, anti-CD34, D2-40, and anti-factor VIII (von Willebrand). She underwent a total mastectomy and is still in remission 20 months later. The authors present a review of the clinical presentation, diagnostic methods, and treatment options.

CONCLUSIONS

This case report demonstrates the importance of long-term follow-up and investigation of even the subtlest cutaneous changes in the breast after radiation treatment, because radiation-induced angiosarcoma is a very aggressive disease that could benefit from early diagnosis and management.