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.

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A distinct morphologic and molecular phenotype has been reported for BRCA1-associated breast cancers; however, the phenotype of BRCA2-associated breast cancers is less certain. To comprehensively characterize BRCA2-associated breast cancers we performed a retrospective case control study using tumors accrued through the Breast Cancer Family Registry. We examined the tumor morphology and hormone receptor status in 157 hereditary breast cancers with germline mutations in BRCA2 and 314 control tumors negative for BRCA1 and BRCA2 mutations that were matched for age and ethnicity. Tissue microarrays were constructed from 64 BRCA2-associated and 185 control tumors. Tissue microarray sections were examined for HER2/neu protein overexpression, p53 status and the expression of basal markers, luminal markers, cyclin D1, bcl2, and MIB1 by immunohistochemistry. The majority of BRCA2-associated tumors and control tumors were invasive ductal, no special-type tumors. In contrast to control tumors, BRCA2-associated cancers were more likely to be high grade (P<0.0001) and to have pushing tumor margins (P=0.0005). Adjusting for grade, BRCA2-associated tumors were more often estrogen receptor positive (P=0.008) and exhibited a luminal phenotype (P=0.003). They were less likely than controls to express the basal cytokeratin CK5 (P=0.03) or to overexpress HER2/neu protein (P=0.06). There was no difference in p53, bcl2, MIB1, or cyclin D1 expression between BRCA2-associated and control tumors. We have demonstrated, in the largest series of BRCA2-associated breast cancers studied to date, that these tumors are predominantly high-grade invasive ductal carcinomas of no special type and they demonstrate a luminal phenotype despite their high histologic grade.

ObjectiveTo identify characteristics of the primary tumor highly associated with lymph node metastases. Summary Background DataRecent enthusiasm for limiting axillary lymph node dissection (ALND) in women with breast cancer may increase the likelihood that nodal metastases will be missed. Identification of characteristics of primary tumors predictive of lymph node metastases may prompt a more extensive surgical and pathologic search for metastases in patients with negative sentinel lymph nodes or limited ALND. MethodsThe authors studied 850 consecutive patients who underwent ALND for T1 breast cancer. Age, tumor size, histopathologic diagnosis, tumor differentiation, presence of lymphatic invasion, and estrogen and progesterone receptor results were studied prospectively. Stepwise logistic regression was used to identify variables independently associated with axillary lymph node metastases. ResultsLymphatic invasion, tumor size, and age were independently associated with lymph node metastases. Fifty-one percent of the 181 patients with lymphatic invasion had axillary lymph node metastases, compared with 19% of the 669 patients without lymphatic invasion. Thirty-five percent of the 470 patients with tumors Ͼ1 cm had nodal involvement compared with 13% of the 380 patients with smaller cancers. Thirtyseven percent of the 63 women younger than age 40 had lymph node involvement compared with 25% of the 787 women older than age 40. Significant correlations were noted between lymphatic invasion and patient age and between lymphatic invasion and tumor size. The proportion of tumors with lymphatic invasion decreased progressively with increasing age and increased with increasing tumor size. ConclusionsAxillary lymph node metastases are most significantly related to lymphatic invasion in the primary tumor, followed, in order of significance, by tumor size and patient age. Axillary nodal metastases should be suspected in the presence of lymphatic invasion of large tumors in young patients.

Based on breast cancer families with multiple and/or early-onset cases, estimates of the lifetime risk of breast cancer in carriers of BRCA1 or BRCA2 mutations may be as high as 85%. The risk for individuals not selected for family history or other risk factors is uncertain. We determined the frequency of the common BRCA1 (185delAG and 5382insC) and BRCA2 (6174delT) mutations in a series of 268 anonymous Ashkenazi Jewish women with breast cancer, regardless of family history or age at onset. DNA was analyzed for the three mutations by allele-specific oligonucleotide hybridization. Eight patients (3.0%, 95% confidence interval [CI] 1.5%-5.8%) were heterozygous for the 185delAG mutation, two (0.75%, 95% CI 0.20-2.7) for the 5382insC mutation, and eight (3.0%, 95% CI 1.5-5.8) for the 6174delT mutation. The lifetime risk for breast cancer in Ashkenazi Jewish carriers of the BRCA1 185delAG or BRCA2 6174delT mutations was calculated to be 36%, approximately three times the overall risk for the general population (relative risk 2.9, 95% CI 1.5-5.8). For the 5382insC mutation, because of the low number of carriers found, further studies are necessary. The results differ markedly from previous estimates based on high-risk breast cancer families and are consistent with lower estimates derived from a recent population-based study in the Baltimore area. Thus, presymptomatic screening and counseling for these common mutations in Ashkenazi Jewish women not selected for family history of breast cancer should be reconsidered until the risk associated with these mutations is firmly established, especially since early diagnostic and preventive-treatment modalities are limited.

CRBP is underexpressed in 24% (95% confidence interval = 12.5%-36.5%) of human breast carcinomas, implying a link between cellular vitamin A homeostasis and breast cancer. We hypothesize that the loss of CRBP restricts the effects of endogenous vitamin A on breast epithelial cells.

PURPOSE: The COVID-19 pandemic has posed significant pressures on healthcare systems, raising concern that related care delays will result in excess cancer-related deaths. Because data regarding the impact on patients with breast cancer are urgently needed, we aimed to provide a preliminary estimate of the impact of COVID-19 on time to treatment initiation (TTI) for patients newly diagnosed with breast cancer cared for at a large academic center. METHODS: We conducted a retrospective study of patients with newly diagnosed early-stage breast cancer between January 1, 2020, and May 15, 2020, a time period during which care was affected by COVID-19, and an unaffected cohort diagnosed between January 1, 2018 and May 15, 2018. Outcomes included patient volume, TTI, and initial treatment modality. Adjusted TTI was compared using multivariable linear regression. RESULTS: Three hundred sixty-six patients were included. There was an 18.8% decrease in patient volume in 2020 (n = 164) versus 2018 (n = 202). There was no association between time of diagnosis (pre-COVID-19 or during COVID-19) and adjusted TTI ( P = .926). There were fewer in situ diagnoses in the 2020 cohort ( P = .040). There was increased use of preoperative systemic therapy in 2020 (43.9% overall, 20.7% chemotherapy, and 23.2% hormonal therapy) versus 2018 (16.4% overall, 12.4% chemotherapy, and 4.0% hormonal therapy) ( P < .001). CONCLUSION: TTI was maintained among patients diagnosed and treated for breast cancer during the COVID-19 pandemic at a single large academic center. There was a decrease in patient volume, specifically in patients with in situ disease and a shift in initial therapy toward the use of preoperative hormonal therapy.