Lobular carcinoma metastasis to endometrial polyps: Insights from a case report and literature analysis

Introduction and importance: Endometrial polyps are rare sites of metastatic breast carcinoma. Such cases have mainly been reported in tamoxifen-related polyps. Case presentation: We describe the case of a 56-year-old woman with invasive lobular carcinoma who was experiencing vaginal bleeding. She underwent hysteroscopy with biopsy. Microscopic examination revealed an endometrial polyp with foci of adenocarcinoma. The morphological features of the tumor matched those of the original breast carcinoma. Clinical discussion: Neoplasms originating from extra-genital sites frequently spread to the female genital organs. However, these metastases are mainly concentrated in the ovaries and vagina, while those affecting the uterus are rare. Among non-genital malignant tumors, mammary carcinoma - particularly the lobular type - is the most common to affect the uterus, followed by digestive and pulmonary tumors. Metastases within an endometrial polyp are particularly unusual. Conclusions: It is crucial to consider metastatic tumors when assessing vaginal bleeding in patients with breast carcinoma. Because of the possibility of endometrial polyps being affected by metastasis, pathologists must examine them rigorously and thoroughly.