Genetic and Clinical Characteristics of Phyllodes Tumors of the Breast

Management of Benign Phyllodes Tumors: A Dutch Population-Based Retrospective Cohort Between 1989 and 2022

BACKGROUND

Phyllodes tumors (PTs) are rare tumors of the breast. The current National Comprehensive Cancer Network (NCCN) guidelines recommend excision of benign PTs, accepting close or positive margins. Controversy about the optimal treatment for benign PTs remains, especially regarding the preferred margin width after surgical excision and the need for follow-up evaluation.

METHODS

A nationwide retrospective study analyzed the Dutch population from 1989 to 2022. All patients with a diagnosis of benign PT were identified through a search in the Dutch nationwide pathology databank (Palga). Information on age, year of diagnosis, size of the primary tumor, surgical treatment, surgical margin status, and local recurrence was collected.

RESULTS

The study enrolled 1908 patients with benign PT. The median age at diagnosis was 43 years (interquartile range [IQR], 34-52 years), and the median tumor size was 30 mm (IQR, 19-40 mm). Most of the patients (95%) were treated with breast-conserving surgery (BCS). The overall local recurrence rate was 6.2%, and the median time to local recurrence was 31 months (IQR, 15-61 months). Local recurrence was associated with bilaterality of the tumor (odds ratio [OR], 4.91; 95% confidence interval [CI], 2.95-28.30) and positive margin status (OR, 2.51; 95% CI 1.36-4.63). The local recurrence rate was 8.9% for the patients with positive excision margins and 4.0% for the patients with negative excision margins. Notably, for 27 patients (22.6%) who experienced a local recurrence, histologic upgrading of the recurrent tumor was reported, 7 (5.9%) of whom had recurrence as malignant lesions.

CONCLUSIONS

This nationwide series of 1908 patients showed a low local recurrence rate of 6.2% for benign PT, with higher recurrence rates following positive margins.

Borderline phyllodes tumour of the breast with eosinophilic inclusion bodies: Case report and molecular sequencing

INTRODUCTION AND IMPORTANCE

The presence of eosinophilic inclusion bodies in the breast is very rare and fewer than 20 cases were described in the literature. Herein we report the first case of borderline phyllodes tumour associated with this kind of cells. To the best of our knowledge, this is also the first time that a molecular sequencing is made targeting the stroma cells with inclusion bodies.

CASE PRESENTATION

A 33-yr-old woman presented a large mass in the right breast. Imaging techniques by mammogram and ultrasonographic examination were performed. After multidisciplinary approach, a breast conserving surgery has been decided. Microscopic analysis, immunohistochemical stains and molecular tests were performed on the lesion. The proposed diagnosis is borderline phyllodes tumour with eosinophilic inclusion bodies.

CLINICAL DISCUSSION

Inclusion bodies are typically found in the infantile digital fibromatosis. Finding them in extradigital fibromatosis is rare. Their signification is still unclear. Some studies suggest a disturbance in the metabolism of proliferating myofibroblasts.

CONCLUSION

The presence of inclusion bodies in breast tumour do not seem to have a prognosis impact. It might be interesting to perform others molecular tests on lesions with eosinophilic inclusion bodies to discover potential mutations.

Clinical outcomes and biomarkers of phyllodes tumors of the breast: A single-center retrospective study

PURPOSE

Phyllodes tumors (PTs) are rare neoplasms with a certain risk of recurrence and/or metastasis. In clinical practice, there is a lack of high-quality clinical studies and unified guidelines to guide the treatment.

MATERIALS AND METHODS

All malignant and recurrence/metastasis PTs were retrospectively collected, which were diagnosed from 2008 to 2022.

RESULTS

A total of 82 patients were enrolled, including 69 malignant and 13 borderline tumors. 96.3% (79/82) received surgical treatment. During a median follow-up of 55.5 months, 20 patients (20/82, 24.4%) had distant metastasis (DM), while 32 (32/82, 39.0%) had local recurrence (LR). Univariate analysis showed the survival of PTs was associated with surgical methods (p < 0.001), tumor size (p = 0.026), and biological behavior (p = 0.017), but not age at diagnosis. In relapsed borderline PTs, we did not find deaths due to disease progression. Patients with DM were all malignant PTs, with disease-progression occurring within 3 years in more than 80% of patients. Among salvage treatments, the combination of antiangiogenic drugs improved the prognosis to some extent, with a significant increase in mPFS (2.77 vs. 1.53 months), but no significant statistical results were obtained (p = 0.168). Lactate dehydrogenase (LDH) was an independent predictor of the prognosis for malignant PTs (p = 0.001, HR = 1.203, 95%CI, 1.082-1.336).

CONCLUSION

Borderline PTs rarely metastasize, and even if LR occurs, surgical resection can lead to long-term survival. In metastatic phyllodes tumors (MPT), systemic therapy is not effective, but antiangiogenic drugs may prolong survival. LDH is an independent prognostic factor for malignant PTs to identify high-risk tumors.

Novel markers in breast pathology

Breast pathology is an ever-expanding database of information which includes markers, or biomarkers, that detect or help treat the disease as prognostic or predictive information. This review focuses on these aspects of biomarkers which are grounded in immunohistochemistry, liquid biopsies and next-generation sequencing.

Genomic characteristics of two breast malignant phyllodes tumors during pregnancy and lactation identified through whole-exome sequencing

Background

The genomic landscape of breast malignant phyllodes tumors (PTs) is not well defined, especially pregnancy-related malignant PTs. To clarify this topic, whole-exome next-generation sequencing (NGS) was performed on tumor samples and paired normal breast tissues from two pregnancy-related malignant PTs, followed by a functional analysis of the genetic alterations.

Methods

DNA from malignant PT samples and matched normal breast tissues of both patients were subjected to molecular profiling. NGS of the whole-exome was performed in a commercial molecular pathology laboratory. Predictive tools were used to estimate genetic variation in somatic and germline genes.

Results

In total, 29 somatic genomic alterations and 18 germline alterations were found in both patients. In Patient 1, 12 aberrations were identified in the tumor tissue, and 9 alterations were identified in matched normal breast tissue. One pathogenic variant in tumor suppressor genes (TP53) was detected in patient 1. In Patient 2, 18 and 10 variants were found in the tumor and matched normal breast tissue, respectively. In Patient 2, pathogenic alterations were identified in two tumor suppressor genes (PTEN and TP53). PTEN and TP53 may be potential drug targets. The functional predictive tools showed that genes of unknown significance for PTs, including FCHO1 in Patient 1, and LRP12 and PKM in Patient 2, were pathogenic. Several genes, including FCHO1, LRP12 and PKM, were shown for the first time to be altered in malignant PTs. A potentially pathogenic germline variant in PRF1, was detected in Patient 1.

Conclusion

Our study first demonstrated somatic and germline gene alterations in two malignant PTs during pregnancy and lactation. These two PTs shared major genetic events, including TP53 mutation, which commonly occurs in malignant PTs; additionally, we identified two potential genes for targeted therapy, TP53 and PTEN. One germline mutation in PRF1 was also detected. These results provide clues regarding tumor pathogenesis and precision therapy development.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02537-w.

Analysis of recurrent molecular alterations in phyllodes tumour of breast: insights into prognosis and pathogenesis

Phyllodes tumour (PT) of breast is a rare biphasic neoplasm. Recent next generation sequencing analyses had revealed novel genetic alterations in PT but lacked a further characterisation of their relationship to different PT features and outcome. Here, using targeted sequencing, we examined a panel of 90 recurrently altered or cancer related genes in 88 PT samples (including 49 benign, 25 borderline and 14 malignant PT). Twenty-three genes showed alterations in at least 8.0% of cases. Alterations were significantly higher with an increasing grade of PT (p=0.033), particularly for copy number alterations. The top ten alterations were TERT promoter (58.0%), MED12 (53.4%), RARA (22.8%), FLNA (19.3%), SETD2 (15.9%), SYNE1 (18.2%), PCLO (15.9%), KMT2D (14.3%), CDKN2A (15.9%) and DNAH11 (14.8%). Alterations in CDKN2A/B, EGFR, TP53, PIK3CA, PTEN and ARID1B (p≤0.039) were associated with a higher grade. Analysing alterations based on common pathways indicated a significant correlation of cell cycle pathway and epigenetic alterations with a higher PT grade (p=0.036 and 0.075 respectively). Interestingly, recurrences were not correlated with tumour grade, but related to the presence of RARA mutation (p=0.011) and the absence of alterations in epigenetic pathway (p=0.031). Analysis of synchronous pair of PT showed more differences in gene mutations with divergent MED12 mutation. By contrast, the recurrent samples showed similar genetic alterations as the primary tumours. In summary, we characterised genetic alterations in PTs of different grades and confirmed the recurrent alterations observed in earlier studies. In addition, current data implicated the roles of cell cycle, epigenetic and RARA changes in PT recurrence and tumourogenesis.

Malignant phyllodes tumor of the breast: a systematic review

Phyllodes tumors (PT) are fibroepithelial neoplasms of the breast showing a peculiar leaf-like appearance. They account for 0.3 to 1% of all primary breast tumors and 2.5% of all fibroepithelial breast tumors. PT are classified into benign, borderline and malignant based upon their stromal morphology with a distribution of 60%, 20%, and 20%, respectively. Malignant PT of the breast constitute an uncommon challenging group of fibroepithelial neoplasms. They have a relatively high tendency to recur, although distant metastasis is uncommon, and nearly exclusive to malignant PT. Adequate surgical resection remains the standard approach to achieve maximal local control. Giant malignant PT are rare and a pose a diagnostic dilemma for pathologists, especially when comprised of sarcomatous elements. This review highlights the morphological features of PT detected in cytology and histology specimens and discusses diagnostic pitfalls and differential diagnosis.

High-Grade Spindle Cell Lesions of the Breast: Key Pathologic and Clinical Updates

Most of the high-grade spindle cell lesions of the breast are malignant phyllodes tumors (MPTs), spindle cell carcinomas (SpCCs), and matrix-producing metaplastic breast carcinomas (MP-MBCs). MPTs have neoplastic spindle stromal cells and a classic leaf-like architecture with subepithelial stromal condensation. MPTs are often positive for CD34, CD117, and bcl-2 and are associated with MED12, TERT, and RARA mutations. SpCCs and MP-MBCs are high-grade metaplastic carcinomas, whereas neoplastic epithelial cells become spindled or show heterologous mesenchymal differentiation, respectively. The expression of epithelial markers must be evaluated to make a diagnosis. SAS, or rare metastatic spindle cell tumors, are seen in the breast, and clinical history is the best supporting evidence. Surgical resection is the standard of care.

Fibroepithelial tumours of the breast-a review

Fibroepithelial tumours of the breast are biphasic neoplasms composed of both epithelial and stromal elements, including the common fibroadenoma and the infrequent phyllodes tumour. The admixture of epithelium and stroma in the fibroadenoma shows intra- and pericanalicular patterns, and may display a variety of histological changes. Fibroadenoma variants include the cellular, juvenile, myxoid and complex forms. The cellular fibroadenoma may be difficult to distinguish from the benign phyllodes tumour. Stromal mitotic activity can be increased in fibroadenomas in the young and pregnant patients. Phyllodes tumours, neoplasms with the potential for recurrence, show an exaggerated intracanalicular growth pattern with broad stromal fronded architecture and stromal hypercellularity. They are graded into benign, borderline and malignant forms based on histological assessment of stromal features of hypercellularity, atypia, mitotic activity, overgrowth and the nature of the tumour borders. Classification of phyllodes tumours is imperfect, compounded by tumour heterogeneity with overlapping microscopic features among the different grades, especially in the borderline category. Malignant phyllodes tumours can metastasise and cause death. Determining which phyllodes tumours may behave aggressively has been difficult. The discovery of MED12 mutations in the pathogenesis of fibroepithelial tumours, together with other gene abnormalities in the progression pathway, has allowed refinements in diagnosis and prognosis.

Two progressed malignant phyllodes tumors of the breast harbor alterations in genes frequently involved in other advanced cancers

Background

The genomic landscape of phyllodes tumors (PTs) of the breast is not well defined, especially in patients with advanced disease. To shed light on this topic, paired primary and progressed tumor samples from two patients with malignant PTs were subjected to next-generation sequencing (NGS) followed by functional analysis of genetic alterations using two prediction tools.

Methods

The DNA of both the primary tumor and distant metastases of Patient 1 and the primary and recurrent tumor of Patient 2 were subjected to molecular profiling. NGS with the FoundationOne® assay was performed in a commercial molecular pathology laboratory. Two in silico prediction tools were used to estimate the pathogenicity of indicated genetic alterations.

Results

In total, 38 genomic alterations were detected, of which 11 were predicted to be probably benign. In Patient 1, 14 aberrations were identified in the primary tumor and 17 in pulmonary metastases, 12 of which were identical. In the primary and recurrent tumor of Patient 2, 17 and 15 sequence variants, respectively, were found, with 13 overlapping findings. Affected genes included seven (TP53, TERT, APC, ARID1A, EGFR, KMT2D, and RB1) of the top 10 most frequently altered genes in other advanced cancer entities, as well as four actionable therapeutic targets (EGFR, KIT, PDGFRA, and BRIP1). Of note, seven genes coding for receptor tyrosine kinases were affected: three in Patient 1 and four in Patient 2. Several genes (e.g. EPHA3, EPHA7, and EPHB1) were shown to be altered for the first time in PTs.

Conclusions

The two progressed malignant PTs investigated here share some of the major genetic events occurring in other advanced cancers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-01986-z.

Genetic differences between benign phyllodes tumors and fibroadenomas revealed through targeted next generation sequencing

Breast fibroepithelial lesions are biphasic tumors which comprise the common benign fibroadenomas (FAs) and the rarer phyllodes tumors (PTs). This study analyzed 262 (42%) conventional FAs, 45 (7%) cellular FAs, and 321 (51%) benign PTs contributed by the International Fibroepithelial Consortium, using a previously curated 16 gene panel. Benign PTs were found to possess a higher number of mutations, and higher rates of cancer driver gene alterations than both groups of FAs, in particular MED12, TERT promoter, RARA, FLNA, SETD2, RB1, and EGFR. Cases with MED12 mutations were also more likely to have TERT promoter, RARA, SETD2, and EGFR. There were no significant differences detected between conventional FAs and cellular FAs, except for PIK3CA and MAP3K1. TERT promoter alterations were most optimal in discriminating between FAs and benign PTs. Our study affirms the role of sequencing and key mutations that may assist in refining diagnoses of these lesions.

SETD2 alterations and histone H3K36 trimethylation in phyllodes tumor of breast

PURPOSE

SETD2 is one of the key epigenetic regulatory genes involved in histone modifications. Its alterations were potentially oncogenic and commonly found in cancers. Interestingly, SETD2 is one of the most frequent mutated genes found exclusively in phyllodes tumor of the breast (PT). However, little has been done to further characterize SETD2 alterations in PT.

METHODS

In this study, we examined the alterations of SETD2 gene and protein expression in a large cohort of PTs. Their correlations with SETD2 downstream target, H3K36me3 expression, and clinicopathologic features in PT were also assessed.

RESULTS

SETD2 mutation was found in 15.9% of our cases and was mostly predicted to be damaging mutations. Interestingly, SETD2 mutations were associated with lower H3K36me3 expression, particularly those with damaging mutations (p = .041). Neither SETD2 mutations nor H3K36me3 expression was associated with PT grading and other clinicopathological features. By contrast, the SETD2 protein expression cannot reflect its mutation status and showed a different trend of clinicopathological correlations from H3K36me3.

CONCLUSIONS

Our findings may suggest a potential involvement of epigenetic regulation via SETD2 alterations and downstream H3K36me3 on PT development. SETD2 mutations may occur early in the pathogenic process of PTs and its loss per se may not be sufficient for progression to malignancy. Exclusive alterations of SETD2 in PT can be used as markers for the diagnosis of fibroepithelial lesions. The association of H3K36me3 with SETD2 mutations may also indicate the value of evaluation of H3K36me3 expression in the diagnosis of fibroepithelial lesions.

Malignant Phyllodes Tumor of the Breast: A Practice Review

Introduction: Phyllodes tumor (PT) of the breast, particularly malignant phyllodes tumor (mPT), is a rare fibroepithelial neoplasm. A complex diagnosis is based on pathologic, radiologic, and clinical findings, with controversies about what is the best therapeutic strategy. Objective: Our objective was to provide an overview of the clinical, pathologic, and therapeutic aspects of this rare tumor. Conclusions: mPT is a rare presentation of breast cancer and a challenge in clinical practice. A multidisciplinary approach should take into account some aspects like pathogenic mutations and hereditary syndromes. Oncologic surgery is the fundamental approach, and the use of adjuvant therapies is still controversial due to the lack of clinical trials. Treatment recommendations should be individualized according to patient risk and preferences. Prospective studies are fundamental to clarifying the best treatment for these tumors.

Phyllodes tumor of the vulva: A case report and literature review highlighting a novel manifestation of Cowden syndrome

Cowden syndrome is a rare hereditary cancer syndrome characterized by a germline PTEN mutation which results in an increased risk of developing breast, thyroid, and endometrial carcinoma, as well as widespread benign hamartomas. Phyllodes tumor (PT) is a rare fibroepithelial tumor that accounts for less than 1% of all breast tumors. As mammary-type glands can be found in the anogenital region, PTs can rarely arise in this location. We describe the presentation, workup and management of a PT of the vulva that developed in a patient with Cowden syndrome. This report represents the first time a vulvar PT has been described in association with Cowden syndrome and should be considered in the differential diagnosis of a slow-growing vulvar mass.

Chemotherapy and targeted treatments of breast sarcoma by histologic subtype

Introduction: Breast sarcomas (BS) are uncommon and often present both diagnostic and therapeutic challenges. Historically, radical surgery has been the mainstay of treatment for localized breast sarcomas. On the other hand, in advanced disease, since they are a heterogeneous group of neoplasms consisting of several different subtypes including angiosarcoma, phyllodes tumor, and pleomorphic undifferentiated sarcoma, there is a lack of proven specific therapy. As a result, their treatment is based on the soft tissue sarcoma (STS) paradigm, whereas histotype-tailored approaches apply to specific subtypes like dermatofibrosarcoma protuberans. To date, advanced stages constitute an incurable form of disease and chemotherapy remains the cornerstone of treatment with the aim of palliation of symptoms and increase in survival.Areas covered: In this manuscript, we review the clinicopathologic characteristics of the most common subtypes of BS, as well as the current treatment landscape of BS, with a particular focus on opportunities and challenges provided by new targeted molecules and immunotherapy.Expert opinion: The treatment approach of advanced BS is based on the pathologic subtype. A true breakthrough has still to be obtained, as the development of new agents in BS suffers from the same weaknesses as in other STS.

Malignant Phyllodes of Breast

Phyllodes tumors of breast (PTB) have been known to an uncommon and particular disease to handle owing to diagnostic ambiguity and unpredictable clinical outcome. Malignant phyllodes tumors (MPT) are diagnosed when there are marked stromal hypercellularity, atypia, increased mitoses of ≥10/10 HPFs, permeative tumor borders, and stromal overgrowth. The presence of a malignant heterologous element (MHE) places the tumor into the malignant category regardless of other histological features. Excision with negative margins should be achieved for recurrent and malignant phyllodes tumor. An ideal margin width remains to be determined, and may need to be considered in relation to factors such as tumor size and cosmesis. Without the convincing evidence of survival benefit, adjuvant RT has revealed more favorable local control rate compared with observation group. Stromal expression of Twist and Foxc2, epithelial-mesenchymal transition marker, was associated with high tumor grade and poor prognosis. Tumor-associated macrophage drives myoblast differentiation and malignant progression of PTB through a CCL18-driven signaling cascade amenable to antibody disruption. Recent targeted sequencing on PTBs provided insights into the molecular pathogenesis and genetic characterization with potential clinical implications.

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.

Droplet-digital PCR reveals frequent mutations in TERT promoter region in breast fibroadenomas and phyllodes tumours, irrespective of the presence of MED12 mutations

BACKGROUND

Breast fibroadenoma (FA) and phyllodes tumour (PT) often have variations of gene mediator complex subunit 12 (MED12) and mutations in the telomerase reverse transcriptase promoter region (TERTp). TERTp mutation is usually tested by Sanger sequencing. In this study, we compared Sanger sequencing and droplet-digital PCR (ddPCR) to measure TERTp mutations in FA and PT samples.

METHODS

FA and PT samples were collected from 82 patients who underwent surgery at our institution from 2005 to 2016. MED12 mutations for all cases and TERTp mutations for 17 tumours were detected by Sanger sequencing. ddPCR was performed to analyse TERTp mutation in all cases.

RESULTS

A total of 75 samples were eligible for analysis. Sanger sequencing detected MED12 mutations in 19/44 FA (42%) and 21/31 PT (68%). Among 17 Sanger sequencing-tested samples, 2/17 (12%) were TERTp mutation-positive. In ddPCR analyses, a significantly greater percentage of PT (19/31, 61%) was TERTp mutation-positive than was FA (13/44, 30%; P = 0.0046). The mutation positivity of TERTp and MED12 did not correlate, in either FA or PT.

CONCLUSIONS

ddPCR was more sensitive for detecting TERTp mutation than Sanger sequencing, being able to elucidate tumorigenesis in FA and PT.

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.

Accuracy of p53 and ki-67 in the graduation of phyllodes tumor, a model for practical application

Background

The accurate graduation of a phyllodes tumor (PT) is critical for effective treatment as it allows correct surgical management, and avoids inadequate excision for malignant or borderline PT, or surgical overtreatment in benign PT. PTs of the breast are notoriously difficult to classify, and reliable differentiation of a benign PT from a borderline or malignant PT can be problematic, especially among relatively inexperienced pathologists. Although several authors acknowledge a strong relationship between the immunohistochemical expression of p53 and Ki-67 and the histopathological grade of PT—with potential impact on diagnostic accuracy—the literature lacks consensus about which cutoff defines a positive index test. The objective of this study is to establish a practical application score that increases the graduation accuracy of PT through the appropriate use of these auxiliary methods.

Methods

A retrospective study cohort of 146 pathology reviewed PTs surgically removed between January 2000 and December 2015. The Ki-67 test was considered positive if > 10% of neoplastic cells showed nuclear staining. The p53 test was considered positive if > 10% of neoplastic nuclear cells showed nuclear staining in a moderate or strong intensity.

Results

Of the 146 PT cases reviewed, 110 were classified as benign, 16 as borderline, and 20 as malignant. The correlation between age and size with benign, borderline, and malignant subgroups was statistically significant (p < 0.001). Significance was observed in the expression of both Ki-67 and p53 in the comparison of benign, borderline, and malignant PT with p < 0.001 and a 95% confidence interval (CI). When correlating the presence of positivity in either of the two index tests with the diagnosis of borderline or malignant PT, we reached a sensitivity of 100% and a specificity of 91.8 (p < 0.001; 95% CI).

Conclusion

We propose a practical methodology to achieve an accurate grade of PT, based on clearly defined and easy to apply cutoffs of a simple immunohistochemical panel of Ki-67 and p53. A PT positive for either of the index tests should be graded as borderline or malignant, so pathologists can use this test to improve accuracy. We hope this new approach might provide the basis for the development of standardization in using p53 and Ki-67 for grading PT.

Olaratumab administered in two cases of phyllodes tumour of the breast: end of the beginning?

Phyllodes tumours of the breast are rare mesenchymal tumours with differential malignant potential. Treatment of choice is radical excision with negative margins. Radiation therapy has shown controversial results in small series. Chemotherapy in the adjuvant setting still remains a matter of debate. Doxorubicin-based chemotherapy is recommended for breast sarcomas' first-line treatment. Herein we present two cases of breast phyllodes tumour treated with the recent combination of doxorubicin and olaratumab.