Phyllodes tumours of the breast: the role of CD34, vascular endothelial growth factor and β-catenin in histological grading and clinical outcome

A Comparative Study on Copy Number Variation in Subtypes of Breast Phyllodes Tumors

Background

Breast phyllodes tumor (PT) is a biphasic tumor and constitutes about 0.3% to 1% of all breast tumors. The PT is histologically classified as benign, borderline, and malignant subtypes. Unlike epithelial breast cancers, PT is derived from breast fibroepithelial tissues, and the genomic information of PT subtypes is still limited.

Objectives

The objectives were to gain a deeper understanding of genomic changes in the progression of PTs from benign and borderline to malignant.

Design

In this study, we used an Affymetrix OncoScan Array to analyze the genome-wide copy number variations (CNVs) and nucleotide point mutations from 3 benign PTs, 3 borderline PTs, and 3 malignant PTs collected from the First Affiliated Hospital of Zhengzhou University.

Methods

DNA was extracted from formalin-fixed paraffin-embedded (FFPE) specimens using the TIANamp FFPE DNA Kit. The DNA was profiled for genome-wide CNV using the Affymetrix OncoScan Array and analyzed using the Nexus Express Chromosome Analysis Suite.

Results

Our in silico variation analysis indicated copy number loss in Xp11.22 to q22.1 of all benign PTs (χ2 = 9, P = .0027) and 22q11.23 and Xq23 in all malignant PTs (χ2 = 12, P = .0005). A copy number gain was observed in 1p13.3 of all borderline PTs (χ2 = 9, P = .0027) and 7p11.2 of all malignant PTs (χ2 = 9, P = .0027). We also found consistent loss of heterozygosity (LOH) in 32 loci of benign PTs, 32 loci of borderline PTs, and 23 loci of malignant PTs. Among the 87 LOH, there were 15 overlapping loci across all PT subtypes. We observed missense mutations of NRAS, KRAS, IDH2, TP53, and a frameshift deletion in PTEN of sequenced PT samples, irrespective of their subtype. Interestingly, a point mutation in EGFR/EGFR-AS1 was only observed in malignant PTs.

Conclusions

Our data suggested that CNV at 7p11.2, 22q11.23, and Xq23 together with a point mutation in EGFR/EGFR-AS1 uniquely presented in malignant PTs may correlate with the progression of PTs.

Patient-derived organoid models of malignant phyllodes tumours for drug sensitivity testing and identification of targeted therapeutic strategies

BACKGROUND

Malignant phyllodes tumours (MPT) of the breast are rare fibroepithelial neoplasms. It exhibits rapid growth, large size, and a high local recurrence rate.

METHODS

In this study, we established novel patient-derived organoid (PDO) models from two primary MPT samples and conducted comprehensive genetic profiling and drug screening.

RESULTS

The PDO models faithfully recapped the histopathological and molecular features of the primary tumours, including stromal overgrowth, leaf-like projections, and the expression of key diagnostic markers. Drug testing revealed significant heterogeneity in response profiles to chemotherapeutic reagents between the two MPT-derived organoids, implying the importance of personalised drug testing. Next-generation sequencing analysis identified recurrent mutations in TP53, RB1, EGFR, ATM, and RECQL4, which correlated with the drug sensitivity profiles observed in the organoid models. Targeted therapeutic drugs, such as Abemaciclib (targeting the RB1 pathway) with an IC50 value of 1.744 µM, and Alflutinib Mesylate (targeting the EGFR pathway) with an IC50 value of 0.9150 µM, exhibited significant cytotoxic effects in the MPT2 organoid models.

CONCLUSIONS

This study highlights the novel application of PDOs for studying the molecular landscape of MPTs and identifying effective therapeutic targets, offering a promising platform for guiding personalised treatment strategies for this rare and challenging cancer.

Versican core protein aids in the diagnosis and grading of breast phyllodes tumor

Phyllodes tumors (PTs) are biphasic fibroepithelial lesions that occur in the breast. Diagnosing and grading PTs remains a challenge in a small proportion of cases, due to the lack of reliable specific biomarkers. We screened a potential marker versican core protein (VCAN) through microproteomics analysis, validated its role for the grading of PTs by immunohistochemistry, and analyzed the correlation between VCAN expression and clinicopathological characteristics. Cytoplasmic immunoreactivity for VCAN was identified in all benign PT samples, among which 40 (93.0 %) showed VCAN-positive staining in ≥50 % of tumor cells. Eight (21.6 %) borderline PT samples showed VCAN-positive staining in ≥50 % of the cells with weak to moderate staining intensity, whereas 29 samples (78.4 %) showed VCAN-positive staining in <50 % of the cells. In malignant PTs, 16 (84.2 %) and three (15.8 %) samples showed VCAN-positive staining in <5 % and 5-25 % of stromal cells, respectively. Fibroadenomas showed a similar expression pattern to benign PTs. Fisher's exact test showed that the percentages of positive cells (P < .001) and staining intensities (P < .001) of tumor cells were significantly different between the five groups. VCAN positivity was associated with tumor categories (P < .0001) and CD34 expression (P < .0001). The expression of VCAN gradually decreases as the tumor categories increases, following recurrence. To the best of our knowledge, our results are the first in the literature to reveal that VCAN is useful for diagnosing and grading PTs. The expression level of VCAN appeared to be negatively associated with PT categories, suggesting that dysregulation of VCAN may be involved in the tumor progression of PTs.

"Growing fibroadenoma": Are there clinical and pathological features predicting a phyllodes tumor on surgical excision?

In cases of growth of FA on imaging, core needle biopsies (CNB) are often performed to rule out phyllodes tumor (PT). We aim to focus on "growing FAs" and to identify clinical and histopathologic features that are likely to predict a PT on excision. Thirty-four FAs with radiologic documentation of growth were included. Various clinical and pathological features such as age, body mass index (BMI), lesion size, and growth rate were recorded. On excision, 17 cases (50 %) were FAs, whereas 16 (47 %) were re-classified as benign PT despite only 19 % being suspicious for PT on CNB. PT patients were older (mean age 42.6) than those with FAs (mean age 28.2), p = 0.0002. All false negative cases demonstrated intracanalicular growth. Mitotic rate was the most significant histologic feature in PT on excision compared to others, such as lesion circumscription and stromal cellularity. Recognition and careful counting of mitotic rate, especially with intracanalicular patterns in growing FAs, can potentially prevent missing a PT on CNB. In patients with "growing FAs" who are ≥40 years of age, excision may be recommended due to the high likelihood of PT diagnosis on excision and high false negative rate on CNB.

Spindle Cell Lesions of the Breast: A Diagnostic Algorithm

CONTEXT.—

Spindle cell lesions of the breast represent a broad spectrum of entities, ranging from nonneoplastic reactive conditions to high-grade malignant tumors. The wide range makes breast spindle cell lesions a diagnostic pitfall.

OBJECTIVE.—

To review the classification of spindle cell lesions of the breast, including clinical features, morphologic characteristics, and the role of immunohistochemistry as well as molecular tools in assisting the differential diagnosis. A diagnostic algorithm will be proposed.

DATA SOURCES.—

Literature and personal experience are the sources for this study.

CONCLUSIONS.—

Spindle cell lesions of the breast can be classified as biphasic or monophasic, with the former including both spindle cell and epithelial components, and the latter including only spindle cell elements. Each category is further subclassified as low or high grade. In the biphasic low-grade group, fibroadenoma and benign phyllodes tumor are the most common lesions. Other uncommon lesions include hamartoma, adenomyoepithelioma, and pseudoangiomatous stromal hyperplasia. In the biphasic high-grade group, borderline/malignant phyllodes tumor and biphasic metaplastic carcinoma are the main lesions to consider. In the monophasic low-grade group, reactive spindle cell nodule, nodular fasciitis, myofibroblastoma, fibromatosis, and fibromatosis-like metaplastic carcinoma have to be considered. In the monophasic high-grade group, the possible lesions are monophasic spindle cell metaplastic carcinoma, primary breast sarcoma, and metastases. Awareness of the clinical history and careful evaluation of any epithelial differentiation (with a large immunohistochemical panel) are crucial in the distinction.

Fibroepithelial Lesions of the Breast: Update on Molecular Profile With Focus on Pediatric Population

CONTEXT.—

This review article derives from the breast pathology lecture at the Eighth Princeton Integrated Pathology Symposium (PIPS VIII).

OBJECTIVE.—

To provide a literature review and update on fibroepithelial lesions of the breast with molecular findings and findings regarding the pediatric population.

DATA SOURCES.—

The sources include extensive literature review, personal research, and experience.

CONCLUSIONS.—

Given significant differences in prognosis and management of fibroepithelial lesions, we aim to provide readers with pertinent definitions, pathomorphology, molecular findings, and management for each diagnosis, with insights on the pediatric population.

Morphological features of 52 cases of breast phyllodes tumours with local recurrence

Typical phyllodes tumours (PTs) of the breast are fibroepithelial neoplasms characterised histologically by stromal hypercellularity and leaf-like structures. However, morphological changes may be atypical in some cases, increasing the difficulty of diagnosis and the likelihood of misdiagnosis. To provide more morphological clues for pathological diagnosis of PTs, we retrospectively analysed 52 PT cases with typical morphological features after recurrence, and summarized the clinicopathological characteristics of the paired primary tumours. We found five special histological features in the primary tumours distinct from classic PTs, namely (1) PTs with epithelioid feature (three cases); (2) PTs with gland-rich feature (eight cases); (3) PTs with fibroadenoma-like feature (20 cases); (4) PTs with myxoid fibroadenoma-like feature (five cases); and (5) PTs with pseudohemangiomatoid stromal hyperplasia–like feature (four cases). All the features can exist independently, and a few cases displayed more than two distinctive features at the same time. In this cohort of recurrent PTs, all the primary tumours were absent of recognisable stromal hypercellularity and leaf-like structures that are the critical diagnostic criteria of PTs; however, they showed some other non-classic characteristics which may provide significant clues for the diagnosis of PTs. Particularly, tumours with epithelioid feature displayed high grade at earlier stages, tumours with fibroadenoma-like feature were most likely to be confused with classical fibroadenomas, and tumours with myxoid feature were prone to be neglected because of their hypocellularity.

Updates on Lobular Neoplasms, Papillary, Adenomyoepithelial, and Fibroepithelial Lesions of the Breast

CONTEXT.—

This review article is a result of the breast pathology lectures given at the Sixth Chinese American Pathologists Association annual diagnostic pathology course in October 2020 (held virtually due to the coronavirus disease 2019).

OBJECTIVE.—

To update recent developments, in this review article, the authors wrote minireviews in the following 4 areas: lobular neoplasm, adenomyoepithelial lesions, papillary lesions, and fibroepithelial lesions.

DATA SOURCES.—

The sources include extensive literature review, personal research, and experience.

CONCLUSIONS.—

With the wide practice of screening mammography, these lesions are not uncommon in image-guided core biopsies and excisional specimens. Many recent developments have emerged in understanding these lesions. We aim to provide readers with concise updates for each of these lesions with a focus on recent updates in definitions, diagnostic criteria, management, and molecular profiles that are most relevant to the daily practice of pathology and patient management.

Uncommon and peculiar soft tissue sarcomas: Multidisciplinary review and practical recommendations. Spanish Group for Sarcoma research (GEIS -GROUP). Part II

Among all Soft Tissue sarcomas there are some subtypes with low incidence and/or peculiar clinical behaviour, that need to be consider separately. Most of them are orphan diseases, whose biological characteristics imply a clearly different diagnostic and therapeutic approach from other more common sarcoma tumors. We present a brief and updated multidiciplinary review, focused on practical issues, aimed at helping clinicians in decision making. In this second part we review these subtypes: Alveolar Soft Part Sarcoma, Epithelioid Sarcoma, Clear Cell Sarcoma, Desmoplastic Small Round Cell Tumor, Rhabdoid Tumor, Phyllodes Tumor, Tenosynovial Giant Cell Tumors, Myoepithelial Tumor, Perivascular Epithelioid Cell Neoplasms (PEComas), Extraskeletal Myxoid Chondrosarcoma, NTRK-fusions Sarcomas. Most of them present their own radiological and histopathological feautures, that are essential to know in order to achieve early diagnosis. In some of them, molecular diagnosis is mandatory, not only in the diagnosis, but also to plan the treatment. On the other hand, and despite the low incidence, a great scientific research effort has been made to achieve new treatment opportunities for these patients even with approved indications. These include new treatments with targeted therapies and immunotherapy, which today represent possible therapeutic options. It is especially important to be attentive to new and potential avenues of research, and to promote the conduct of specific clinical trials for rare sarcomas.

Apatinib treatment is effective for metastatic malignant phyllodes tumors of the breast: a case report

Background

We report a rare case of malignant phyllodes tumors (MPT) with partial response to apatinib.

Case presentation

A 26-year-old woman had a palpable mass in her right breast for over a year. After resection, pathology indicated malignant phyllodes tumor. Eleven months after surgery, she underwent reoperation for a lung nodule, which demonstrated lung metastasis. She refused chemotherapy and was rehospitalized six months later due to leg pain. Pelvic mass biopsy revealed metastatic malignant phyllodes tumor. After concurrent chemoradiotherapy of the pelvic mass, multiple lung metastases emerged. Subsequent treatment with apatinib 500 mg/day resulted in a reduction in mass size and partial response. She survived for more than 8 months.

Conclusion

The present case showed the potential therapeutic effects of apatinib in patients with MPT.

Fibroepithelial lesions revisited: implications for diagnosis and management

Fibroepithelial lesions of the breast, comprising the fibroadenoma and phyllodes tumour, are a unique group of neoplasms that share histological characteristics but possess different clinical behaviour. The fibroadenoma is the commonest benign breast tumour in women, while the phyllodes tumour is rare and may be associated with recurrences, grade progression and even metastasis. The diagnosis of fibroadenoma is usually straightforward, with recognised histological variants such as the cellular, complex, juvenile and myxoid forms. The phyllodes tumour comprises benign, borderline and malignant varieties, graded using a constellation of histological parameters based on stromal characteristics of hypercellularity, atypia, mitoses, overgrowth and the nature of tumour borders. While phyllodes tumour grade correlates with clinical behaviour, interobserver variability in assessing multiple parameters that are potentially of different biological weightage leads to significant challenges in accurate grade determination and consequently therapy. Differential diagnostic considerations along the spectrum of fibroepithelial tumours can be problematic in routine practice. Recent discoveries of the molecular underpinnings of these tumours may have diagnostic, prognostic and therapeutic implications.

Expression of lymphoid enhancer-binding factor 1 in breast fibroepithelial lesions

Phyllodes tumors (PTs) are rare epithelial-mesenchymal tumors of the breast with malignant potential. Here, we evaluate the nuclear expression of lymphoid enhancer-binding factor 1 (LEF-1), a transcription factor downstream of Wnt/β-catenin signaling, in fibroepithelial lesions of the breast. Excised fibroepithelial lesions of the breast were retrospectively reviewed, blinded to the original diagnosis, and classified according to World Health Organization (WHO) criteria. A tissue microarray (TMA) was composed with two representative cores from each case, including 24 benign lesions, 11 borderline phyllodes, and 8 malignant PTs. β-Catenin, LEF-1, p120, and E-cadherin immunohistochemistry was performed on the TMA, and staining was quantified. The malignant/borderline PTs showed higher stromal LEF-1 expression than benign tumors (P < 0.001). Stromal cells expressed LEF-1 in 100% (16/16 of core TMA) of malignant phyllodes, compared with 73% (16/22) borderline and 27% (13/48) benign tumors. The average LEF-1 H-score was 24.9, 6.1, and 1.5 for malignant, borderline, and benign tumors, respectively. Nuclear expression of β-catenin in the stromal component was more often seen in malignant than in borderline and benign tumors (44% versus 32% and 23%, respectively). Nine TMA cores of malignant tumors without nuclear β-catenin staining demonstrated LEF-1 expression. Both LEF-1 and nuclear β-catenin showed expression in the majority of borderline/malignant PTs suggesting a biological progression of Wnt/β-catenin pathway activation in the stromal component from benign to malignant tumors. Inhibitors for the Wnt/β-catenin pathway may provide alternative treatment options in the future for malignant or metastatic PTs.

Correlation between peripheral blood neutrophil-lymphocyte ratio and CD34 expression in prostate cancer

Backgrounds

The association of neutrophil-lymphocyte ratio (NLR) and CD34 expression level with PSA level, Gleason score, and clinical stage was investigated in patients with prostate cancer. The correlation between NLR and CD34 expression was also investigated to provide evidence supporting the use of NLR for predicting the prognosis of prostate cancer patients.

Methods

Clinical data of 75 patients diagnosed with prostate cancer by prostate aspiration biopsy were retrospectively analyzed. The correlation between NLR, CD34 expression, and clinicopathological characteristics was analyzed using the χ2 test and one-way analysis of variance. The correlation between NLR and CD34 was determined using the Pearson coefficient. Disease free survival was estimated by Kaplan-Meier analysis.

Results

Both NLR and CD34 expression were significantly positively correlated with PSA, Gleason score, and clinical stage (P < 0.05 both). Patients in the NLR^High/CD34^High group were characterized by high PSA level and Gleason score and late clinical stage. NLR was positively correlated with CD34 expression (r = 0.529, P < 0.001).

Conclusions

Pretreatment NLR was a valuable marker of prognosis in prostate cancer. NLR is positively correlated with CD34 expression.

Morphologic and genetic heterogeneity in breast fibroepithelial lesions-a comprehensive mapping study

Breast fibroepithelial lesions (FELs) encompass the common fibroadenoma (FA) and relatively rare phyllodes tumour (PT); the latter entity is usually classified as benign, borderline or malignant. Intratumoural heterogeneity is frequently present in these tumours, making accurate histologic evaluation challenging. Despite their rarity, PTs are an important clinical problem due to their propensity for recurrence and, in the case of malignant PT, metastasis. Surgical excision is the mainstay of management. Recent work has uncovered myriad genetic alterations in breast FELs. In this study, exome sequencing was performed on seven cases of morphologically heterogeneous breast FELs, including FAs, PTs of all grades, and a case of metaplastic spindle cell carcinoma arising in PT, in order to elucidate their intratumoural genetic repertoire. Gene mutations identified encompassed cell signalling, tumour suppressor, DNA repair and cell cycle regulating pathways. Mutations common to multiple tumour regions generally showed higher variant allele frequency. Frequent mutations included MED12, TP53, RARA and PIK3CA. Histological observations of increased cellular density and pleomorphism correlated with mutational burden. Phylogenetic analyses revealed disparate pathways of possible tumour progression. In summary, histological heterogeneity correlated with genetic changes in breast FELs.

Core needle biopsy diagnosis of fibroepithelial lesions of the breast: a diagnostic challenge

Fibroepithelial lesions (FEL) of the breast are biphasic neoplasms consisting of proliferative epithelial and stromal components and include fibroadenoma, phyllodes tumour and periductal stromal tumour. Core needle biopsy (CNB) is a commonly used diagnostic modality for investigation of breast lesions. As the accurate diagnosis of FEL requires integrated assessment of both epithelial and stromal components, this may create problems in small biopsies with limited sampling. In this review, common problems encountered in CNB of FEL are discussed, including establishing a diagnosis of borderline/malignant phyllodes tumour in a biopsy consisting of malignant spindle cells, differentiating phyllodes tumour from fibroadenoma on CNB, grading of phyllodes tumour of intermediate histological grade and assessment of periductal stromal tumours. The approaches are detailed systematically based on histology, immunohistochemistry and molecular characterisation. This comprehensive approach may aid in dealing with the overlapping histological appearance of FEL and sampling limitations of CNB.

Recurrent borderline phyllodes tumor in nipple: a rare case report and review of the literature

Phyllodes tumor (PT) of the breast is a rare tumor. They are usually located in the four quadrants of the mammary gland and may also appear below the nipple. Although there have been a number of cases reported, here we report a very rare case of this tumor in an unusual location. The patient has been diagnosed with right breast borderline PT, who accepted breast-conserving surgery. Twelve months after surgery we found right nipple enlargement, without nipple discharge, ipsilateral and contralateral breast without palpable mass. Interestingly, ultrasound showed a lesion in the right nipple: a hypoechoic mass with a diameter of 2.0 cm was seen in the nipple, with no significant calcification. The patient underwent nipple-sparing mastectomy without postoperative adjuvant radiotherapy. Histopathological and immunohistochemical analysis demonstrated a borderline PT. There were no signs of recurrence after two years of follow-up. We consider that wide surgical resection and negative margin are still the main methods for the treatment of recurrent borderline PTs.

Spindle Cell Lesions of the Breast on Fine-Needle Aspiration Biopsy: A Miscellany of Masses

A variety of primary breast and metastatic lesions to the breast can present with spindle cell cytomorphology. These lesions may range from benign reactive or inflammatory lesions to high-grade malignancies. Spindle cell lesions of the breast are not often seen on fine-needle aspiration biopsy (FNAB) but need to be correctly managed when they are encountered. While mesenchymal lesions of the breast have a spindle morphology, lesions derived from the epithelium and myoepithelium can be spindled as well. By assessing if the lesion comprises spindle cells only or if other components such as epithelial cells are apparent and then determining whether the spindle cells appear bland or pleomorphic, together with close clinicoradiologic correlation and prudent use of ancillary tests, a variety of lesions can be diagnosed on FNAB. However, core needle biopsy or excision biopsy may be required in some patients. The cytomorphology, ancillary studies, and clinicoradiologic findings of a range of spindle cell lesions of the breast are further discussed.

Local Recurrence of Benign, Borderline, and Malignant Phyllodes Tumors of the Breast: A Systematic Review and Meta-analysis

BACKGROUND

This systematic review and meta-analysis aimed to investigate local recurrence (LR) rates among the three grades (benign, borderline, and malignant) of phyllodes tumors (PTs). The study also assessed various risk factors for LR.

METHODS

Electronic articles published between 1 January 1995 and 31 May 2018, were searched and critically appraised. The authors independently reviewed the abstracts and extracted data for LR rates and LR risk factors.

RESULTS

The review incorporated 54 studies with 9234 individual cases. The pooled LR rates were 8% for benign, 13% for borderline, and 18% for malignant PTs. The risk of LR was significantly increased by borderline versus benign PTs (odds ratio [OR] 2.00; 95% confidence interval [CI] 1.68-2.38) and malignant versus borderline PTs (OR 1.28; 95% CI 1.05-1.55). The significant risk factors for LR were mitoses, tumor border (infiltrating vs. pushing), stromal cellularity (moderate/severe vs. mild), stromal atypia (severe vs. mild/absent), stromal overgrowth (severe vs. mild/absent), and tumor necrosis (positive vs. negative). Age and tumor size were not associated with LR risk. The subgroup analysis showed that breast-conserving surgery versus mastectomy and positive versus negative surgical margins were significantly associated with an increased LR risk only in malignant PTs.

CONCLUSIONS

The risk of LR was significantly increased from benign to borderline to malignant PTs. Mitoses, tumor border, stromal cellularity, stromal atypia, stromal overgrowth, tumor necrosis, type of surgery, and surgical margin status may be risk factors for LR. Different management strategies could be considered for different PT grades.

Benign Fibromyxoid Lesion of the Breast: A Distinct Entity From Benign Spindle Cell Tumors of the Mammary Stroma?

Myxoid lesions of the breast can be diagnostically challenging entities. We report 4 cases of CD34+ fibromyxoid lesion that have been previously diagnosed as “benign myxoid lesion,” “nodular mucinosis,” or “mammary myofibroblastoma, myxoid type” on the basis of CD34-positivity. The lesions were microscopically well circumscribed and composed of a paucicellular spindle cell proliferation in a background of myxoid stroma. No epithelial component was identified. The spindle cells showed immunohistochemical reactivity for CD34 and smooth muscle actin. Based on morphologic and immunohistochemical similarities between these cases and myxoid myofibroblastoma, we compared 4 myxoid lesions with cases of typical myofibroblastoma, utilizing retinoblastoma (Rb) antibody and fluorescent in situ hybridization for 13q14 gene rearrangement (encoding the Rb gene). The myxoid lesions showed retention of Rb protein by immunohistochemistry, whereas Rb expression was lost in cases of myofibroblastoma. We identified loss of 13q14 in 3 of 4 cases of myofibroblastoma. Notably, 13q14 gene rearrangement was not observed in any of the myxoid lesions. Our data show that there is at least a subset of CD34+ fibromyxoid lesions that, despite overlapping morphologic and immunohistochemical phenotype and proposed common histogenesis with myofibroblastomas, is genetically distinct from the latter based on Rb analysis.

A Diagnostic Approach to Fibroepithelial Breast Lesions

Fibroepithelial breast lesions encompass a heterogeneous group of neoplasms that range from benign to malignant, each exhibiting differing degrees of stromal proliferation in relation to the epithelial compartment. Fibroadenomas are common benign neoplasms that may be treated conservatively. Phyllodes tumors are relatively rare lesions, and classified as benign, borderline, or malignant based on histologic evaluation of various parameters. The diagnostic interpretation of "gray-zone" fibroepithelial lesions often imposes formidable demands on a pathologist's skills. This article offers practical recommendations for the diagnostic workup of these lesions, including the appropriate utilization of ancillary investigations and the approach to core needle biopsies.

Increased β‑catenin and c-myc expression predict aggressive growth of non-functioning pituitary adenomas: An assessment using a tissue microarray-based approach

Non-functional pituitary adenomas (NFPAs) account for 80% of pituitary adenomas with the majority of these exhibiting recurrences post-surgery. Overexpression of β-catenin and c‑myc is common in numerous invasive tumors. The present study sought to investigate the correlation of β‑catenin and c‑myc expression levels with aggressive growth and recurrence of NFPAs, using immunohistochemical examination of tissue microarrays. Tissue microarrays comprised 212 NFPAs specimens and 10 healthy specimens as controls. NFPAs were categorized as non‑aggressive or aggressive. Immunohistochemical examination was performed to determine the expression of β‑catenin and c‑myc. Correlation of the expression levels of β‑catenin and c‑myc with clinicopathological parameters, including aggressiveness and recurrence, were assessed by univariate, multivariate and logistic regression analysis. Increased expression of β‑catenin and c‑myc was detected in the majority of aggressive NFPAs specimens (71.1 and 88.7%, respectively). There was a significant positive correlation between β‑catenin and c‑myc expression and aggressiveness [P=0.001, Odds Ratio (OR)=4.011; P<0.001, OR=30.833]. Only β‑catenin expression demonstrated a significant correlation with recurrence in NFPAs (P=0.021, OR=2.571). β‑catenin and c‑myc were demonstrated to be potential biomarkers for aggressive NFPAs and in the future, β-catenin may serve as a marker for aggressive behavior and recurrence in NFPAs.

Multiplatform molecular profiling identifies potentially targetable biomarkers in malignant phyllodes tumors of the breast

Malignant phyllodes tumor is a rare breast malignancy with sarcomatous overgrowth and with limited effective treatment options for recurrent and metastatic cases. Recent clinical trials indicated a potential for anti-angiogenic, anti-EGFR and immunotherapeutic approaches for patients with sarcomas, which led us to investigate these and other targetable pathways in malignant phyllodes tumor of the breast. Thirty-six malignant phyllodes tumors (including 8 metastatic tumors with two cases having matched primary and metastatic tumors) were profiled using gene sequencing, gene copy number analysis, whole genome expression, and protein expression. Whole genome expression analysis demonstrated consistent over-expression of genes involved in angiogenesis including VEGFA, Angiopoietin-2, VCAM1, PDGFRA, and PTTG1. EGFR protein overexpression was observed in 26/27 (96%) of cases with amplification of the EGFR gene in 8/24 (33%) cases. Two EGFR mutations were identified including EGFRvIII and a presumed pathogenic V774M mutation, respectively. The most common pathogenic mutations included TP53 (50%) and PIK3CA (15%). Cases with matched primary and metastatic tumors harbored identical mutations in both sites (PIK3CA/KRAS and RB1 gene mutations, respectively). Tumor expression of PD-L1 immunoregulatory protein was observed in 3/22 (14%) of cases. Overexpression of molecular biomarkers of increased angiogenesis, EGFR and immune checkpoints provides novel targeted therapy options in malignant phyllodes tumors of the breast.

In phyllodes tumors of the breast expression of SPARC (osteonectin/BM40) mRNA by in situ hybridization correlates with protein expression by immunohistochemistry and is associated with tumor progression

Secreted protein acidic and rich in cysteine (SPARC) plays an essential role in tumor invasion and metastasis. The present work was undertaken to detect expression of SPARC mRNA in phyllodes tumors (PTs) and its association with SPARC protein expression. This study also evaluated expression of SPARC mRNA and its correlation between grade and clinical behavior of PTs. In addition, we assessed in PTs the association of expression of SPARC with that of matrix metalloproteinase (MMP)-2 and of MMP-9. SPARC mRNA expression was determined by RNAscope in situ hybridization (ISH) in 50 benign, 22 borderline, and 10 malignant PTs using a tissue microarray. Furthermore, we applied immunohistochemistry (IHC) to examine expression of SPARC, MMP-2, and MMP-9. SPARC mRNA appeared to be concentrated mainly in the stromal compartment of PTs. IHC staining patterns of SPARC protein showed concordance with SPARC mRNA ISH results. Stromal SPARC expression increased continuously as PTs progress from benign through borderline to malignant PTs, both at mRNA (using ISH) (P = 0.044) and protein level (using IHC) (P = 0.000). The recurrence percentage was higher in the stromal SPARC mRNA or protein-positive group than in the SPARC-negative group but this difference was not statistically significant. Stromal SPARC mRNA and protein expression was associated with PT grade and correlated with MMP-2 expression. These results indicate that SPARC-mediated degradation of the extracellular matrix, and its possible association with MMPs, might contribute to progression of PTs.

Relationship between ultrasound elastography and myofibroblast distribution in breast cancer and its clinical significance

The study investigated the relationship between ultrasound elastography (USE) scoring and myofibroblast distribution with expression features of α-SMA + /CD34− in patients of Uyghur and Han ethnicities with breast masses in Xinjiang, China. The data was used to evaluate its clinical significance in the early diagnosis of breast cancer. A total of 300 patients with breast masses were included in the study, which involved conventional sonography and USE, with histopathologic diagnosis as the reference standard. Myofibroblast distribution was investigated by detecting the expression levels of α-SMA and CD34 in lesions using immunohistochemistry and real-time PCR. Out of 300 lesions, 185 were histologically malignant and 115 benign. The mean elasticity score for malignant lesions was significantly higher than for benign lesions. The expression level of α-SMA was elevated while the expression level of CD34 was lower in malignancies, compared with benign lesions. The expression of α-SMA was positively associated with the USE scores, while a negative relationship was observed between CD34 expression and USE scoring. The combination of USE and molecular diagnosis provides a promising modality for the early diagnosis and evaluation of the risks in particular types of breast cancer.

Phyllodes tumours of the breast: a consensus review

Phyllodes tumours constitute an uncommon but complex group of mammary fibroepithelial lesions. Accurate and reproducible grading of these tumours has long been challenging, owing to the need to assess multiple stratified histological parameters, which may be weighted differently by individual pathologists. Distinction of benign phyllodes tumours from cellular fibroadenomas is fraught with difficulty, due to overlapping microscopic features. Similarly, separation of the malignant phyllodes tumour from spindle cell metaplastic carcinoma and primary breast sarcoma can be problematic. Phyllodes tumours are treated by surgical excision. However, there is no consensus on the definition of an appropriate surgical margin to ensure completeness of excision and reduction of recurrence risk. Interpretive subjectivity, overlapping histological diagnostic criteria, suboptimal correlation between histological classification and clinical behaviour and the lack of robust molecular predictors of outcome make further investigation of the pathogenesis of these fascinating tumours a matter of active research. This review consolidates the current understanding of their pathobiology and clinical behaviour, and includes proposals for a rational approach to the classification and management of phyllodes tumours.

IMP3 Is Strongly Expressed in Malignant Phyllodes Tumors of the Breast

Background. Phyllodes tumors (PTs) of the breast are rare biphasic neoplasms and are classified as benign, borderline, or malignant. Many biological markers have been studied to discriminate between different grades of PTs. IMP3 is a member of the insulin-like growth factor II mRNA binding protein (IMP) family and is expressed in developing tissues during embryogenesis, whereas in adult tissues it is found only at low or undetectable levels. IMP3 is considered a marker of biological aggressiveness in many cancers, including breast and lung. The aim of this study was to evaluate the immunohistochemical expression of IMP3 in a series of PTs and to determine its association with histological grade and clinical outcome. Materials and Methods. We reviewed retrospectively 62 cases of PTs including their recurrences and 20 cases of fibroadenoma. PTs have been classified as benign in 40 cases, borderline in 13 cases, and malignant in 9 cases. Results. There were significant differences in IMP3 expression: in malignant PTs IMP3 expression was higher (56% of cases) than in borderline (15%) and benign cases (5%), ( P = .001). Fibroadenoma showed no expression for IMP3. IMP3 expression was different in cases with recurrence than cases without recurrence. Furthermore, 3 of the recurrences had a higher histological grade with a positive IMP3 expression compared with the primary tumor. Conclusions. This is the first study evaluating the IMP3 immunohistochemical expression in PTs. Its expression correlates with histological grade and could be used in the differential diagnosis of fibroepithelial tumors and in predicting a more aggressive behavior.

CD117 expression in breast phyllodes tumors correlates with adverse pathologic parameters and reduced survival

CD117 (c-kit) is a type III receptor tyrosine kinase encoded by the KIT gene. Deregulation of expression and mutations in the gene are implicated in various tumors. Reports of CD117 expression in phyllodes tumors have been controversial. We aim to investigate the protein expression of CD117 and mutations in the KIT gene in phyllodes tumors, and correlate the findings with pathological parameters and clinical outcome. A total of 272 cases were included in this study. CD117 expression was investigated by immunohistochemistry on tissue microarray sections. Toluidine blue staining was performed to indicate mast cells. Overall, 28 (10%) cases were CD117 positive. CD117 expression was significantly associated with tumor grade (P<0.001), increased stromal hypercellularity (P=0.003), stromal atypia (P=0.01), and stromal mitotic activity (P<0.001), permeative microscopic margins (P=0.002), and presence of hemorrhage (P=0.001). Expression was also associated with poorer overall survival (P=0.003). Nineteen cases were further selected for mutation screening through the Affymetrix OncoScan platform. No mutation of the KIT gene was found. Despite a lack of mutations in the KIT gene, CD117 protein expression is associated with unfavorable pathological parameters and poorer prognosis, suggesting an underlying role in the biology of phyllodes tumors.

Utility of Ki-67, CD10, CD34, p53, CD117, and Mast Cell Content in the Differential Diagnosis of Cellular Fibroadenomas and in the Classification of Phyllodes Tumors of the Breast

Adequate management of phyllodes tumors of the breast (PTB) remains a challenge because of the difficulty in correctly establishing preoperative diagnosis. The aim of this study was to evaluate the usefulness of Ki-67, CD10, CD34, p53, CD117, and of the number of mast cells in the differential diagnosis of benign PTB and cellular fibroadenomas (CFs) as well as in the grading of PTB. Fifty-one primary PTB and 14 CFs were examined by immunohistochemistry.When evaluating CD117 expression, higher epithelial expression was present in CF as well as an increased number of mast cells in benign PTB. Stromal expression of Ki-67, CD10, CD34, and p53 were relevant to PTB grading, of which the first 3 showed significance in the distinction of benign and borderline PTB, as well as between benign and malignant PTB. P53 was relevant only for the discrimination between benign and malign PTB. None of the markers showed significance in distinguishing between borderline and malign PTB.