Metastasis of Invasive Ductal Carcinoma of the Breast to the Uterine Cervix 30 Years Post-Mastectomy: A Case Report.

Metastasis of invasive ductal carcinoma of the breast to the uterine cervix is rare, with only one report of a case occurring more than 20 years after the primary surgery. A 69-year-old woman presented with abnormal uterine cervical cytology (atypical glandular cells without tumor diathesis) 30 years after undergoing breast cancer surgery. Magnetic resonance imaging revealed a 38-mm cervical mass. Modified radical hysterectomy was performed. The resected specimen exhibited an immunohistochemical profile of GATA3(+)/mammaglobin(+)/PAX8(-), which definitively excluded primary cervical adenocarcinoma and confirmed the diagnosis of metastatic invasive ductal carcinoma. Crucially, although the primary tumor was hormone receptor-positive, cervical metastasis exhibited receptor conversion to HER2-positive status. This case underscores the importance of considering metastatic breast cancer in the differential diagnosis of cervical masses in breast cancer survivors regardless of the disease-free interval. This further highlights the necessity for receptor re-evaluation in metastatic lesions to guide appropriate targeted therapy.