Abstract：
Borderline Brenner tumors (BBT) have a range of morphology that shows considerable overlap with that of malignant Brenner tumors (MBT). In particular, two histological patterns of BBT can be particularly challenging: 1) BBT with intraepithelial carcinoma (BBT-IEC) and 2) BBT with a small nested pattern (BBT-SNP). BBT-IEC is characterized by a tumor with the low-power non-infiltrative silhouette of a conventional BBT, but with increased cytological atypia and mitotic activity similar to that of MBT. Conversely, BBT-SNP is characterized by a complex proliferation of small tumor nests that closely resemble the infiltrative growth pattern of MBT, but without the obligate cytologic atypia and mitotic activity of MBT. We suggest that the combination of p16, p53 and Ki-67 may be helpful in distinguishing these 2 patterns of BBT from both conventional BBT and from MBT. While both conventional BBT and BBT-IEC show a null pattern of p16 expression, our case of BBT-IEC showed aberrant p53 overexpression, albeit with a maturation pattern similar to that described for TP53 mutant mucinous ovarian carcinoma and differentiated vulvar intraepithelial neoplasia (dVIN). Similarly, while BBT-SNP shows an infiltrative-like growth pattern similar to that of MBT, our case also showed a wild-type pattern of p53 expression and a Ki-67 proliferative index similar to areas with conventional BBT histology. In conclusion, in our small case series, we show that the use of immunohistochemistry for p53 and Ki-67 may help to distinguish challenging patterns of BBT from MBT. Further studies are needed to validate this finding in a larger case cohort.
摘要：
边缘性布伦纳肿瘤（BBT）的形态范围与恶性布伦纳肿瘤（MBT）的形态重叠。特别是,BBT的两种组织学模式可能特别具有挑战性：1）上皮内癌的BBT（BBT-IEC）和2）小嵌套模式的BBT（BBT-SNP）。BBT-IEC的特征是肿瘤具有传统BBT的低功率非浸润性轮廓，但与MBT相似的细胞学异型性和有丝分裂活性增加。相反，BBT-SNP的特征是小肿瘤巢的复杂增殖，与MBT的浸润性生长模式非常相似，但没有MBT的专性细胞学异型性和有丝分裂活性。我们建议p16，p53和Ki-67的组合可能有助于将这两种BBT模式与常规BBT和MBT区分开。虽然传统的BBT和BBT-IEC都显示p16表达的空模式，我们的BBT-IEC病例显示p53异常过表达，尽管成熟模式与TP53突变型粘液性卵巢癌和分化型外阴上皮内瘤变（dVIN）相似。同样，虽然BBT-SNP显示出类似于MBT的渗透生长模式，我们的病例还显示p53表达的野生型模式和Ki-67增殖指数与传统BBT组织学区域相似.总之,在我们的小案例系列中，我们发现,使用免疫组织化学检测p53和Ki-67可能有助于区分BBT和MBT的挑战性模式.需要进一步的研究来在更大的病例队列中验证这一发现。
