Two cases of uterine metastasis from breast cancer: Radiologic-pathologic correlation and literature review

Uterine metastasis from breast cancer is extremely rare and often misdiagnosed as primary uterine neoplasm due to nonspecific imaging features. We present 2 cases illustrating the radiologic-pathologic correlation of uterine metastases. Patient 1 was an 81-year-old woman with a history of invasive ductal carcinoma. Pelvic Magnetic resonance imaging (MRI) revealed a well-circumscribed uterine mass with intermediate signal intensity (SI) on T2-weighted images (T2WI), high SI on diffusion-weighted images (DWI), and minimal contrast enhancement. Patient 2 was a 67-year-old woman with prior invasive lobular carcinoma, presenting with abnormal uterine bleeding 18 years after initial treatment. Magnetic resonance imaging (MRI) revealed a lobulated mass in the posterior uterine wall showing heterogeneous T2 SI and high SI on DWI, resembling a degenerative leiomyoma. In both cases, the myometrium was diffusely thickened, with low to mildly high SI on T2-weighted images (T2WI) and mildly high SI on DWI. No discrete lesions were observed in the cervix on imaging. Radiologic-pathologic correlation confirmed metastatic involvement of the uterus, including the cervix, either diffusely or focally. MR findings may be influenced by the stromal composition of metastatic lesions and by the morphologic diversity of metastases-features that parallel those seen in primary breast cancer. Because metastatic lesions may mimic leiomyomas or remain occult, diagnosis should not rely on T2 SI alone. Rather, the combination of multiplicity, DWI hyperintensity, and clinical history should be considered. Clinicians should maintain a low threshold for endometrial biopsy in conjunction with serum tumor marker assessment during the diagnostic evaluation of uterine lesions.