Departments of Anatomic Pathology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.
Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
Mod Pathol. 2018 Jul;31(7):1073-1084. doi: 10.1038/s41379-018-0032-8. Epub 2018 Feb 14.
Mammary fibroepithelial lesions encompass a wide spectrum of tumors ranging from an indolent fibroadenoma to potentially fatal malignant phyllodes tumor. The criteria used for their classification based on morphological assessment are often challenging to apply and there is no consensus as to what constitutes an adequate resection margin. We studied a retrospective cohort of 213 fibroepithelial lesions in 178 patients (80 fibroadenomas with unusual features and 133 phyllodes tumors: 63 benign, 41 borderline, and 29 malignant) in order to describe the spectrum of changes within each group, with special emphasis on margin evaluation. Outcome data were available for 153 fibroepithelial lesions in 139 patients (median 56 months, range 3-249 months). Positive final margin (tumor transected), age < 50 years and a predominantly myxoid stroma were statistically significant predictors of local recurrence, while age > 50, stromal overgrowth, diffuse marked atypia, necrosis and mitotic index of ≥ 10 per 10 HPF were predictive of distant metastases. Tumors with satellite/bulging nodules were at a significantly higher risk to have a final positive resection margin. Our findings highlight important aspects of the interpretation and reporting of fibroepithelial lesions: the amount of myxoid stroma and the presence of satellite nodules are clinically relevant and should be routinely assessed and reported; infiltrative border might not be a prerequisite for the diagnosis of malignant phyllodes tumor, while the presence of tumor necrosis, massive stromal overgrowth or mitotic index of ≥ 25 per 10 HPF is diagnostic of malignant phyllodes tumor. On the other hand, increased mitotic index outside of the range of the World Health Organization guidelines in the absence of other worrisome features should be treated with caution, as it can be found in benign tumors.
乳腺纤维上皮性病变包括广泛的肿瘤谱，从良性的纤维腺瘤到潜在致命的恶性叶状肿瘤。基于形态评估的分类标准应用起来具有挑战性，而且对于什么构成充分的切缘尚无共识。我们研究了 178 例患者的 213 例纤维上皮性病变的回顾性队列（80 例具有不典型特征的纤维腺瘤和 133 例叶状肿瘤：63 例良性、41 例交界性和 29 例恶性），以描述每组内的变化范围，特别强调边缘评估。139 例患者的 153 例纤维上皮性病变有结局数据（中位数为 56 个月，范围为 3-249 个月）。阳性的最终切缘（肿瘤被横切）、年龄<50 岁和主要为黏液样基质是局部复发的统计学显著预测因子，而年龄>50 岁、间质过度生长、弥漫性显著异型性、坏死和核分裂指数≥10/10 HPF 是远处转移的预测因子。有卫星/隆起结节的肿瘤有显著更高的最终阳性切缘风险。我们的发现强调了纤维上皮性病变的解释和报告的重要方面：黏液样基质的量和卫星结节的存在具有临床相关性，应常规评估和报告；浸润性边界可能不是恶性叶状肿瘤的诊断前提，而肿瘤坏死、大量间质过度生长或核分裂指数≥25/10 HPF 是恶性叶状肿瘤的诊断特征。另一方面，在没有其他令人担忧特征的情况下，超出世界卫生组织指南范围的高核分裂指数应谨慎处理，因为它也可见于良性肿瘤中。
