Molecular classification of breast phyllodes tumors: validation of the histologic grading scheme and insights into malignant progression

Phyllodes tumors of the breast are rare fibroepithelial neoplasms with a potential for recurrence. Current histological classification is not always predictive of clinical behavior. The aim of this study was to identify genetic changes associated with the development of borderline and malignant phyllodes tumors in an Asian population, and to assess if genetic data supported the categorization of these tumors into the existing three grades of benign, borderline, and malignant. Expression profiling of 21 phyllodes tumors (6 benign, 10 borderline, 5 malignant) was performed using Affymetrix U133Plus 2.0 GeneChips^®. Gene expression among benign, borderline, and malignant tumors was compared and a 29 gene list was able to classify them according to their histologic grade. Among these 29 genes are those responsible for matrix formation, cell adhesion, epidermis formation, and cell proliferation. Comparative genomic microarray analysis showed that the most common chromosomal alteration associated with borderline and malignant tumors was 1q gain, and an increasing number of chromosomal changes was noted with increasing histological grade. Upregulation of HOXB13 was seen in malignant relative to borderline phyllodes tumors and further investigated by immunohistochemistry in a corresponding set of formalin-fixed, paraffin-embedded tumors. HOXB13 protein overexpression was found to be correlated with stromal hypercellularity and atypia (P = 0.03, P = 0.039, respectively) and may be implicated in the development of malignant phyllodes tumors.     

Increased epidermal growth factor receptor (EGFR) expression in malignant mammary phyllodes tumors

Mammary phyllodes tumors are uncommon stromal-epithelial neoplasms, and are divided into benign, borderline malignant and frankly malignant groups on the basis of their histological features. Accumulating evidence shows that epidermal growth factor receptor (EGFR) is involved in the pathogenesis and progression of many malignancies. This study investigated 453 phyllodes tumors (296 benign, 98 borderline, 59 malignant) for EGFR expression using immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) for gene amplification. The staining was correlated to tumor margin status, degree of malignancy, stromal cellularity, mitotic activity, nuclear pleomorphism and stromal overgrowth. Cases with strong positive IHC staining were selected for FISH. The overall positive rate for EGFR was 16.2% (48/296), 30.6% (30/98) and 56% (33/59) for benign, borderline malignant and frankly malignant phyllodes tumors, respectively. FISH demonstrated egfr gene amplification in 8% of immunohistochemically positive cases. The results of this study provide strong evidence that EGFR overexpression is involved in the pathogenesis of phyllodes tumors, although gene amplification may not be the major underlying mechanism for overexpression.     

乳腺复发性叶状肿瘤临床病理分析

目的:探讨乳腺复发性叶状肿瘤临床及病理特征。方法:收集2011年01月至2019年12月在我院进行手术治疗的叶状肿瘤病例,并找出其中复发的病例,分析复发病例的临床及病理组织学特征。结果:叶状肿瘤137例,共有10例为复发病例,其中9例为单次复发,1例复发两次,复发病例中良性叶状肿瘤7例,交界性叶状肿瘤2例,恶性叶状肿瘤1例。所有的肿物均为局部复发,良性、交界及恶性叶状肿瘤复发率分别为5.9%、15.4%、20%。其中3例（30%）出现组织学升级,1例良性叶状肿瘤复发为交界性叶状肿瘤,1例交界性叶状肿瘤复发为恶性叶状肿瘤,1例良性叶状肿瘤第一次复发为交界性叶状肿瘤,第二次复发为恶性叶状肿瘤。免疫组化标记CD117、CD34、CD10、p53、p16在原发及复发肿瘤中表达无差异。Ki67增殖指数在复发病例中均升高,并且核分裂数也增多。结论:良性、交界性、恶性叶状肿瘤均可复发,其中恶性叶状肿瘤复发率最高,肿瘤多为局部复发,部分肿瘤复发后出现组织学升级,复发后肿瘤细胞增殖活性增强。     

Molecular Cytogenetic Characterization in Four Pediatric Pheochromocytomas and Paragangliomas

Pheochromocytomas (PCCs) are rare tumors among children and adolescents and therefore are not genetically well characterized. The most frequently observed chromosomal changes in PCC are losses of 1p, 3q and/or 3p, 6q, 17p, 11q, 22q, and gains of 9q and 17q. Aberrations involving chromosome 11 are more common in malignant tumors. Unfortunately information about gene aberrations in childhood PCC’s is limited. We used comparative genomic hybridization (CGH) and array comparative genomic hybridization (aCGH) to screen for copy number changes in four children suffering from pheochromocytoma or paraganglioma. Patients were diagnosed at the age 13 or 14 years. Bilateral pheochromocytoma was associated with von Hippel-Lindau syndrome (VHL). Multiple paraganglioma was associated with a germline mutation in SDHB. We found very good concordance between the results of CGH and aCGH techniques. Losses were observed more frequently than gains. All cases had a loss of chromosome 11 or 11p. Other aberrations were loss of chromosome 3 and 11 in sporadic pheochromocytoma, and loss of 3p and 11p in pheochromocytoma, which carried the VHL mutation. The deletion of chromosome 1p and other changes were observed in paragangliomas. We conclude that both array CGH and CGH analysis identified similar chromosomal regions involved in tumorigenesis of pheochromocytoma and paragangliomas, but we found 3 discrepancies between the methods. We didn’t find any, of the proposed, molecular markers of malignancy in our benign cases and therefore we speculate that molecular cytogenetic examination may be helpful in separating benign and malignant forms in the future.     

Histologic features predict local recurrence after breast conserving therapy of phyllodes tumors

Background: Pathologists can distinguish benign phyllodes tumors, which very rarely metastasize, from malignant phyllodes tumors, which metastasize in approximately one fourth of patients. However, whether these same histologic criteria can be used to predict the likelihood that a phyllodes tumor will locally recur after breast conserving therapy remains controversial.Study Design: Since few patients with malignant phyllodes tumors have been treated with breast conserving surgery in any individual series, the literature was reviewed using a Medline search.Results: After local excision, 21 (111/540), 46 (18/39), and 65 (26/40) of patients with benign, borderline, and malignant phyllodes tumors, respectively, recurred in the breast. Following wide local excision, 8 (17/212), 29 (20/68), and 36 (16/45) of patients with benign, borderline, and malignant phyllodes tumors recurred in the breast.Conclusions: Malignant phyllodes tumors are much more likely than benign phyllodes tumors to recur in the breast after breast conserving surgery. This high rate of local recurrence of borderline and malignant phyllodes tumors suggests that wide local excision is less than optimal therapy, and challenges us to look for methods to improve local tumor control.     

DNA sequence copy number changes in gastrointestinal stromal tumors: tumor progression and prognostic significance

To identify genetic changes related to tumor progression and find out diagnostic and prognostic genetic markers in gastrointestinal stromal tumors (GISTs), 95 tumor samples (24 benign GISTs, 36 malignant primary GISTs, and 35 GIST-metastases) from 60 patients were studied using comparative genomic hybridization. DNA copy number changes were detected in all samples. Benign GISTs had a mean of 2.6 aberrations/ sample (losses:gains, 5:1) and significantly fewer DNA copy number changes and fewer gains than malignant primary and metastatic GISTs (P < 0.01). High-level amplifications were not seen in benign GISTs. Malignant primary GISTs had a mean of 7.5 aberrations/tumor (losses: gains, 1.6:1), whereas the mean number of aberrations/metastatic GIST was 9 (losses:gains, 1.8:1). Frequent changes observed in all GIST groups included losses in chromosome arms 1p (51%), 14q (74%), and 22q (53%). Gains and high-level amplifications at 8q and 17q were significantly more frequent in metastatic GISTs (57 and 43%) than in benign GISTs (8 and 0%; P < 0.001) and malignant primary GISTs (33 and 25%; P < 0.05). Gains and high-level amplifications at 20q were only seen in malignant primary and metastatic GISTs (P < 0.01), and gains at 5p were not detected in benign GISTs (P < 0.01). Losses in chromosome arm 9p were never seen in benign tumors (P < 0.001), and they were more frequent in metastatic GISTs than in malignant primary GISTs (63 and 36%; P < 0.05). Losses in 13q were less frequent in benign GISTs than in malignant primary (P < 0.05) and metastatic (P < 0.01) GISTs. Our results show that several DNA copy number changes are related to the behavior of GISTs and can be used as prognostic markers for tumor progression.     

Keratin 15, transcobalamin I and homeobox gene Hox-B13 expression in breast phyllodes tumors: novel markers in biological classification

Breast phyllodes tumors are rare neoplasms which present challenges for histological classification. Microscopic features are not always predictive of clinical behavior, and scarce data exist on the prognostic role of biological markers. Our study evaluated a series of 145 phyllodes tumors diagnosed at the Department of Pathology, Singapore General Hospital between 2006 and 2009, incorporating 91 (62.8%) benign, 40 (27.6%) borderline, and 14 (9.7%) malignant phyllodes tumors. Antibodies to keratin 15 (KRT15), transcobalamin I (TCN1), and homeobox gene Hox-B13 (HOXB13) were applied to sections cut from tissue microarray blocks. KRT15 and TCN1 positivity was defined when there was reactivity of 1% or more stromal cells, while HOXB13 positivity was defined using a H-score of 100 and above. Positive immunohistochemical expression for KRT15, TCN1, and HOXB13 was seen in 21 (14.5%), 96 (66.2%), and 66 (45.5%) of tumors, respectively. Stromal expression of KRT15, TCN1, and HOXB13 was significantly correlated with tumor grade (P < 0.001, P < 0.001, P = 0.012), stromal hypercellularity (P = 0.005, P < 0.001, P = 0.023), mitotic activity (P < 0.001), and microscopic borders (P = 0.006, P < 0.001, P = 0.011). Co-expression of TCN1 and HOXB13 was seen in 21 of 91 (23.1%) benign, 18 of 40 (45.0%) borderline, and 11 of 14 (78.6%) malignant tumors, suggesting that the dual-marker panels of TCN1 and HOXB13 might be helpful in classifying borderline and malignant tumors. Although expression of TCN1 alone was present in all malignant and 34 of 40 (85.0%) borderline tumors, a combined panel with HOXB13 excluded some benign cases and was a better discriminant for a significant proportion of borderline and malignant tumors.     

乳腺叶状肿瘤的X线表现

目的探讨乳腺叶状肿瘤X线影像学特点,并与其病理对照,以提高对该病的诊断准确率。方法回顾性分析经手术病理证实有完整乳腺X线资料的乳腺叶状肿瘤50例共54个病灶,其中良性26个、交界性22个、恶性6个。结果 54个病灶中表现为伴或不伴钙化的肿块50个(92.6%),假阴性4个(7.4%)。50个肿块病变中良性23个、交界性21个、恶性6个。形状以分叶状、圆形或卵圆形最多见,分别占62.0%(31/50)、10.0%(5/50)、26.0%(13/50)。肿块边缘主要表现为清楚或部分清楚部分模糊,占80%(40/50),其余肿块呈浸润状及细小分叶状边缘,分别占18.0%(9/50)和2.0%(1/50)。肿块表现为高密度占74.0%(37/50),等密度占26.0%(13/50)。3个病灶肿块内含有钙化。边缘特征在良性与恶性肿瘤、交界性肿瘤与恶性肿瘤之间有明显差异,P_(良-恶)=0.003,P_(良-恶)=0.044。结论乳腺叶状肿瘤主要X线表现为分叶状或圆形、卵圆形的高密度肿块,钙化少见;边缘特征可在一定程度上提示良恶性叶状肿瘤的区别。     

Jejunal intussusception due to malignant phyllodes tumor of the breast

Phyllodes tumors are rare fibroepithelial neoplasms of the breast; classified as benign, borderline, or malignant based on the mitotic activity, cellular atypia, and stromal overgrowth. Wide surgical excision is the treatment of choice. The most common locations for metastasis are lung, bone, and liver; small intestinal metastasis is extremely rare. Here we present the first patient with jejunal metastases and intussusception due to malignant phyllodes tumor of the breast. Adjuvant treatment of malignant phyllodes tumor needs to be investigated.     

The clinical features and prognosis of phyllodes tumors: a single institution experience in Taiwan

Background and objectives

The aim of this study was to document the clinical and pathological features of a single institutional series of Asian patients with phyllodes tumors, and to determine the prognosis, the adequate management and the predictive histological features.

Methods

The clinical data were retrospectively studied from the medical records and the pathological data from the Department of Pathology were utilized to identify 33 patients diagnosed with phyllodes tumors between 2003 and 2010.

Results

Eight patients had benign tumors, 13 borderline and 12 malignant. Nine patients (27 %) had recurrence. No patients classified as benign phyllodes tumors had recurrence, but those with malignant phyllodes tumors had a high recurrence rate (41 %). The 5-year disease-free survival was 59 %. The 5-year overall survival was 81 %. The width of surgical margin was not related to disease recurrence and stromal overgrowth was the only prognostic factor in terms of disease-free survival and overall survival.

Conclusions

The phyllodes tumors of borderline and malignant classification in Asian patients had a high recurrence rate. Clinical and pathological factors, except for stromal overgrowth, cannot predict disease recurrence. Further molecular research is warranted.     

Gains in chromosomes 7, 8q, 15q and 17q are characteristic changes in malignant but not in benign peripheral nerve sheath tumors from patients with Recklinghausen's disease

In order to investigate typical genomic alterations in patients with Recklinghausen's disease (NF1) we studied one from each of the six patients with NF1 several benign and/or malignant tumors. By means of comparative genomic hybridization (CGH) gained results from six benign neurofibromas and 14 malignant peripheral nerve sheath tumors (MPNSTs) were compared with four benign peripheral nerve sheath tumors (BPNSTs) from patients without NF1. In all 14 MPNSTs DNA sequence copy number changes were detected with a mean value of 13.5 imbalances per sample. The most frequent gains were in 8q, 17q (12 tumors each), 7p, 15q (ten tumors each), and 7q (nine tumors). We found ten high-level amplifications in nine of the 14 samples. In two cases, the high-level amplification involved 7p14-pter and 17q24-qter as well. The most frequent loss was in 17p (seven tumors). The benign neurofibromas from NF1-patients and the sporadic BPNSTs revealed only partially DNA sequence copy number changes without any distinct pattern. The gains of #7, 8q, 15q, and 17q were found exclusively in MPNSTs but not in neurofibromas and are supposed to be associated with malignant tumor progression. In comparison of the results of the 14 MPNSTs from NF1-patients with the results of previously published 20 sporadic MPNSTs, we found that the gain of 8q occurs most frequently in both tumor groups. Of course additionally in the sporadic MPNSTs there were more frequent gains of 5p, #6, and statistically significant gains of 20q. On the other hand in the MPNSTs from NF1-patients the most frequent gains were found in #7, and statistically significant in 15q, and 17q.     

Chromosomal aberrations in sporadic pituitary tumors

Pituitary adenomas are common intracranial neoplasms that may be hormone-secreting or nonfunctional. Genetic defects associated with some pituitary tumors have been identified, although our understanding of the underlying molecular mechanisms remains incomplete. We have studied 75 sporadic pituitary tumors, representing the major clinical subtypes, by comparative genomic hybridization (CGH) with the aim of assessing for DNA copy number changes. CGH revealed chromosomal imbalances in 34 adenomas (45.3%), whereby gains were 4.9 times more frequently observed than losses. Most of the genetic alterations detected by CGH affected entire chromosomes (108/131, 82.4%). Gain of genetic material was observed predominantly on chromosomes X (24/75, 32%), 19 (12/75, 16%), 12 (6/75, 6.7%), 7 and 9 (5/75, 6.7%), whereas loss of DNA sequences most frequently affected chromosomes 11 (4/75, 5.3%), 13 and 10 (3/75, 4%). There were no significant differences in the CGH results for the individual clinical subtypes of pituitary tumors. These results reveal a nonrandom pattern of chromosomal alterations in pituitary tumors, in particular gains of entire chromosomes, and this may contribute to the development of such neoplasms.     

Genetic evidence for early divergence of small functioning and nonfunctioning endocrine pancreatic tumors: gain of 9Q34 is an early event in insulinomas.

The malignant potential among endocrine pancreatic tumors (EPTs) varies greatly and can frequently not be predicted using histopathological parameters. Thus, molecular markers that can predict the biological behavior of EPTs are required. In a previous comparative genomic hybridization study, we observed marked genetic differences between the various EPT subtypes and a correlation between losses of 3p and 6 and gains of 14q and Xq and metastatic disease. To search for genetic alterations that play a role during early tumor development, we have studied 38 small (< or =2 cm) EPTs, including 24 insulinomas and 10 nonfunctioning EPTs. Small EPTs are usually classified as clinically benign tumors in the absence of histological signs of malignancy. Using comparative genomic hybridization, we identified chromosomal aberrations in 27 EPTs (mean, 4.1). Interestingly, the number of gains differed strongly between nonfunctioning and functioning EPTs (3.4 versus 1.5, respectively; P = 0.0526), as did the number of aberrations in the benign (n = 30) and malignant (n = 8) tumors (3 versus 8.4, respectively; P = 0.0022). In the insulinomas, 9q gain (common region of involvement: 9q34) was most common (50%) and in nonfunctioning EPTs, gain of 4p was most common (40%). Most frequent losses in insulinomas involved 1p (20.8%), 1q, 4q, 11q, Xq, and Y (all 16.7%) and in nonfunctioning EPTs, 6q. Losses of 3pq and 6q and gains of 17pq and 20q proved to be strongly associated with malignant behavior in all of the small EPTs (P < or = 0.0219). Our results demonstrate marked genetic differences between small functioning and nonfunctioning EPTs, indicating that these subtypes evolve along different genetic pathways. In addition, our study endorses the importance of chromosomes 3 and 6q losses to discriminate EPTs with a malignant behavior from benign ones.     

C-kit overexpression correlates with KIT gene copy numbers increases in phyllodes tumors of the breast

Breast Cancer Research and Treatment - We determined c-kit expression in the stroma and epithelia of benign, borderline, and malignant phyllodes tumors (PTs), respectively, as well as the...     

Cystosarcoma phyllodes of the breast: a case report in a 12-year-old girl

Breast tumors in adolescents are very rare and mostly benign. Fibroadenomas are the most frequent, but within the extensive differential diagnosis, the phyllodes tumor must be mentioned, which accounts for about 1% of breast tumors and the diagnosis of which is very rare in patients younger than 20 years. There are no specific symptoms or radiological images to distinguish phyllodes tumor from fibroadenoma; therefore, histological examination is mandatory for diagnosis. Histology also allows the classification of phyllodes tumor into benign, borderline, or malignant types for appropriate surgical treatment: freemargin excision in benign tumors and mastectomy in the other two types. Fortunately, the majority of these tumors are benign, and treatment maximizes breast conservation with free infiltration margins surgery, given that this fact is the most important factor to prevent local recurrence. In this article, we describe a rare case of borderline cystosarcoma phyllodes in a 12-year-old girl.     

TERT promoter mutations are frequent and show association with MED12 mutations in phyllodes tumors of the breast

Background:

Phyllodes tumors are rare fibroepithelial neoplasms of the breast, which carry the potential risk of local recurrence and metastasis. Phyllodes tumors share several histological features with fibroadenomas, and no widely accepted markers for distinguishing these lesions have been identified.

Methods:

We analyzed molecular abnormalities related to telomere elongation in tumors, including TERT promoter mutations, as well as loss of expression of ATRX and DAXX, in a total of 104 phyllodes tumors and fibroadenomas.

Results:

Sequencing analyses showed that TERT promoter mutations were frequent in phyllodes tumors (30/46, 65%), but rare in fibroadenomas (4/58, 7%). Among phyllodes tumors, the mutations were more frequent in borderline tumors (13/15, 87%), but were also common in benign (9/18, 50%) and malignant tumors (8/13, 62%). Remarkably, all but one TERT promoter-mutated tumor also contained MED12 mutations, indicating that these mutations are strongly associated (P=8.4 × 10⁻⁶). Expression of ATRX and DAXX, as evaluated by immunohistochemistry, was retained in all tumors.

Conclusions:

Our observations suggest a critical role of TERT promoter mutations, in cooperation with MED12 mutations, in the development of phyllodes tumors. Because TERT promoter mutations are rare among fibroadenomas, their detection may be of potential use in discriminating between phyllodes tumors and fibroadenomas.     

Phyllodes tumor of the breast

PURPOSE: To better identify prognostic factors for local control and survival, as well as the role of different therapeutic options, for phyllodes tumors, a rare fibroepithelial neoplasm of the breast. METHODS AND MATERIALS: Data from 443 women treated between 1971 and 2003 were collected from the Rare Cancer Network. The median age was 40 years (range, 12-87 years). Tumors were benign in 284 cases (64%), borderline in 80 cases (18%), and malignant in 79 cases (18%). Surgery consisted of breast-conserving surgery (BCS) in 377 cases (85%) and total mastectomy (TM) in 66 cases (15%). Thirty-nine patients (9%) received adjuvant radiotherapy (RT). RESULTS: After a median follow-up of 106 months, local recurrence (LR) and distant metastases rates were 19% and 3.4%, respectively. In the malignant and borderline group (n = 159), RT significantly decreased LR (p = 0.02), and TM had better results than BCS (p = 0.0019). Multivariate analysis revealed benign histology, negative margins, and no residual disease (no RD) after initial treatment and RT delivery as independent favorable prognostic factors for local control; benign histology and low number of mitosis for disease-free survival; and pathologic tumor size < or = 3 cm and no tumor necrosis for overall survival. In the malignant and borderline subgroup multivariate analysis TM was the only favorable independent prognostic factor for disease-free survival. CONCLUSIONS: This study showed that phyllodes tumor patients with no RD after treatment have better local control. Benign tumors have a good prognosis after surgery alone. In borderline and malignant tumors, TM had better results than BCS. Thus, in these forms adjuvant RT should be considered according to histologic criteria.     

Immunohistochemical profile of phyllodes tumors of the breast

The immunohistochemical profiles of 16 cases of phyllodes tumor of the breast (9 benign and 7 malignant) from 15 patients were examined by the labeled streptavidin biotin method. The expression of Ki-67, p53, bcl-2, alpha-smooth muscle actin (alpha-SMA), desmin, S-100 protein, estrogen receptor (ER), and progesterone receptor (PgR) was analyzed. The number of Ki-67-positive stromal cell nuclei of malignant phyllodes tumor were significantly more prominent than the benign tumors. The p53 expression on the stromal cell nuclei showed a significant difference between malignant and benign cases (86% vs 22%; p<0.05). bcl-2 was regularly seen on the luminal cell cytoplasm and stromal cell labeling showed no significant difference between malignant and benign cases (29% vs 33%). Stromal cells were alpha-SMA positive but refractory among cases, and desmin and S-100 protein were negative. PgR was expressed in all 16 cases and ER in most cases (12/16) the expression of which was restricted to luminal epithelial cell nuclei. These findings indicate that the Ki-67 labeling index and p53 expression in the stroma would be a good diagnostic parameter distinguishing benign tumors from malignant tumors. However, the absence of steroid receptor expression in stromal cells suggests the ineffectiveness of hormonal therapy for phyllodes tumor of the breast.     

Phyllodes tumors of the breast: The British Columbia Cancer Agency experience

Purpose

Phyllodes tumors of the breast are uncommon fibroepithelial lesions for which optimal management remains unclear. This retrospective population-based study reports treatment and outcomes for patients with phyllodes tumors and evaluates characteristics that influence outcome.

Cystosarcoma phyllodes of the breast

Forty-nine patients with cystosarcoma phyllodes (CP), aged 13-81 years, (mean 35.2 years) were studied. Tumor size ranged from 1.9 to 14 cm (mean 5.2 cm). Mean follow-up period was 11.3 years. Tumors were histopathologically graded as benign, borderline or malignant. Forty-two tumors were diagnosed as benign; 4 borderline and 3 malignant. Six patients had recurrent disease within 6 years of their first surgery. Statistical analysis showed that age was not a significant factor for predicting recurrence or malignant histopathology. Five patients with relapse had borderline or malignant tumors larger than 4 cm. The histopathologic diagnosis was concordant with the clinical course. Multivariate analysis showed that tumor size and histology were significant and independent factors for disease-free interval. Breast-conserving surgery with a wide tumor-free margin is preferred in CP, and close follow-up is advised in cases with malignant or borderline histopathology and tumors larger than 4 cm.