2025 Volume 42 Issue 3 Pages 224-229
Tumor-to-tumor metastasis is rare. Here, we report a case of a female patient in her 80s with metastatic lobular carcinoma of the breast in the uterine leiomyoma, presenting as a nodule-in-nodule appearance. Because 18F-fluorodeoxyglucose positron emission tomography/computed tomography detected the uterine tumor before receiving neoadjuvant chemotherapy for locally advanced breast cancer, she was referred to our hospital and total hysterectomy and bilateral salpingo-oophorectomy was performed. The lesion was an 80×60 mm tumor bulging into the uterine cavity exhibiting a nodule-in-nodule appearance. Histologically, multiple metastatic foci of lobular breast carcinoma were identified within the leiomyoma. Although tumor-to-tumor metastasis is a rare condition, it need to be cited as a differential diagnosis in the case with advanced cancer.
