Department of Biopathology, Institut Bergonié, Comprehensive Cancer Centre, Bordeaux, France.
Medical College, Université Bordeaux, Bordeaux, France.
Histopathology. 2022 Jan;80(2):304-313. doi: 10.1111/his.14544. Epub 2021 Sep 22.
Breast hamartomas are an under-recognised lesion because they lack a distinctive microscopic appearance. Microscopic diagnosis can often conclude 'no significant lesion' or 'normal breast tissue', leading to repeated biopsies and diagnostic delay. We describe the histological, immunohistochemical and radiological features of breast hamartomas with the aim of identifying specific signs to facilitate their diagnosis and to differentiate them from normal breast and fibroepithelial lesions.
Forty-seven breast hamartomas were reassessed (histological diagnosis and imaging features). An immunohistochemical study [oestrogen receptor (ER), progesterone receptor (PR), CD34, high-mobility group A2 (HMGA2)] was performed. On breast imaging, hamartomas most often presented as probably benign solid masses with circumscribed margins and variable densities. Histologically, breast hamartomas resembled normal breast, although their stromal component was predominant, separating randomly scattered epithelial elements with areas of pure collagenous stroma. Pseudoangiomatous stromal hyperplasia (PASH) was present in 93.6% of cases and CD34 antibody highlighted intralobular, perilobular and interlobular distribution of CD34-positive fibroblasts. By comparison, CD34 was mainly expressed in the intralobular normal breast tissue stroma. Hamartoma stromal cells expressed HMGA2, ER and PR in 79%, 66% and 76.3% of our cases, respectively, compared to 7.7%, 23% and 19% in normal breast tissue, respectively (P < 0.0001; P = 0.0005; P < 0.0001).
After ascertaining that core needle biopsy is effectively intralesional, breast hamartomas can be diagnosed with confidence by taking into account the presence of stromal changes, PASH, interlobular distribution of CD34-positive fibroblasts, HMGA2 and hormonal receptor stromal expression.
乳腺错构瘤是一种认识不足的病变，因为其缺乏独特的显微镜下表现。显微镜诊断通常会得出“无明显病变”或“正常乳腺组织”的结论，导致重复进行活检和诊断延迟。我们描述了乳腺错构瘤的组织学、免疫组织化学和影像学特征，旨在确定特定的特征以促进其诊断，并将其与正常乳腺和纤维上皮病变区分开来。
重新评估了 47 例乳腺错构瘤（组织学诊断和影像学特征）。进行了免疫组织化学研究[雌激素受体（ER）、孕激素受体（PR）、CD34、高迁移率族蛋白 A2（HMGA2）]。在乳腺影像学上，错构瘤最常表现为可能为良性的实性肿块，边界清楚，密度不均。组织学上，乳腺错构瘤类似于正常乳腺，尽管其基质成分占主导地位，随机分离散在的上皮成分，伴有纯胶原基质区。93.6%的病例存在假血管瘤样间质增生（PASH），CD34 抗体突出显示 CD34 阳性成纤维细胞在小叶内、小叶周围和小叶间的分布。相比之下，CD34 主要表达在小叶内的正常乳腺组织基质中。我们的病例中，错构瘤基质细胞分别有 79%、66%和 76.3%表达 HMGA2、ER 和 PR，而正常乳腺组织中分别为 7.7%、23%和 19%（P<0.0001；P=0.0005；P<0.0001）。
在确认核心针活检是有效的病灶内活检后，通过考虑间质变化、PASH、CD34 阳性成纤维细胞的小叶间分布、HMGA2 和激素受体基质表达，可以有信心地诊断乳腺错构瘤。
