Woo Ha Young, Jung Yoon Yang, Kim Hyun-Soo
Department of Pathology, Chung-Ang University Gwangmyeong Hospital, Gyeonggi-do, Republic of Korea.
Department of Pathology, Myongji Hospital, Hanyang University College of Medicine, Gyeonggi-do, Republic of Korea;
In Vivo. 2025 Jul-Aug;39(4):2456-2463. doi: 10.21873/invivo.14046.
BACKGROUND/AIM: Metastasis of extragenital malignancies to the female genital tract, particularly the uterus, is exceedingly rare. Invasive lobular carcinoma (ILC) is the most common histological type of breast carcinoma that metastasizes to gynecologic organs.
A 42-year-old woman receiving tamoxifen presented with an irregularly thickened endometrium on transvaginal ultrasonography. She had previously undergone bilateral partial mastectomies - eight years prior for right-sided invasive ductal carcinoma, and three years prior for left-sided ILC. Hysteroscopic evaluation revealed an endometrial polyp. Microscopic examination of the polypectomy specimen showed variably sized, irregularly shaped branching glands embedded in densely fibrotic stroma. Within the stroma, monomorphic tumor cells with hyperchromatic, eccentrically located nuclei were arranged in single files, thin cords, or nests. Immunostaining revealed that the tumor cells were positive for GATA-binding protein 3 and negative for paired box 8, supporting a diagnosis of metastatic carcinoma from the breast. The final pathological diagnosis was metastatic ILC involving a tamoxifen-associated endometrial polyp.
Although rare, breast carcinoma may metastasize to endometrial polyps. Clinicians and pathologists should consider this possibility when evaluating abnormal ultrasonographic findings in the female genital tract, particularly in patients with a history of breast carcinoma receiving tamoxifen therapy. Abnormal ultrasonographic findings in the uterus of such patients warrant a comprehensive diagnostic workup to exclude metastatic disease.
背景/目的：生殖器外恶性肿瘤转移至女性生殖道，尤其是子宫，极为罕见。浸润性小叶癌（ILC）是最常转移至妇科器官的乳腺癌组织学类型。
一名42岁接受他莫昔芬治疗的女性经阴道超声检查显示子宫内膜不规则增厚。她曾接受过双侧部分乳房切除术——8年前因右侧浸润性导管癌，3年前因左侧ILC。宫腔镜检查发现一个子宫内膜息肉。对息肉切除标本的显微镜检查显示，在致密纤维化间质中可见大小不一、形状不规则的分支腺体。在间质内，具有深染、偏心核的单形性肿瘤细胞呈单行、细索状或巢状排列。免疫染色显示肿瘤细胞GATA结合蛋白3阳性，配对盒8阴性，支持乳腺癌转移的诊断。最终病理诊断为转移性ILC累及他莫昔芬相关子宫内膜息肉。
尽管罕见，但乳腺癌可能转移至子宫内膜息肉。临床医生和病理学家在评估女性生殖道超声检查异常结果时，尤其是有乳腺癌病史且接受他莫昔芬治疗的患者，应考虑这种可能性。此类患者子宫超声检查异常结果需要进行全面的诊断性检查以排除转移性疾病。
