Benign Phyllodes Tumor and Ductal Carcinoma in situ Coexist in the Same Breast Tumor: A Case Report and Review of the Literature

Background: Breast phyllodes tumor (PT), the rare fibroepithelial mammary tumor is composed by mesenchymal and epithelial components, only 1%~2% of which were accompanied by epithelial breast cancer. The incidence of non-invasive ductal carcinoma (DCIS) arising in benign PTs is even rarer. There is no certain treatment for it currently because of the low incidence of PT with DCIS. Case Description: Here, we report a 57-year-old female patient who was diagnosed with ductal carcinoma in situ arising in a benign phyllodes tumor of the breast. Mastectomy and sentinel lymph nodes biopsy were performed, and endocrine therapy was administrated to the patient. No recurrence was noted during follow-up. Conclusion: Since PTs are prone to recurrence, adjuvant therapy should be considered comprehensively by the histopathological results after surgical treatment. In addition, regular follow-up is recommended.