Youngest case of ductal carcinoma in situ arising within a benign phyllodes tumour: A case report.

INTRODUCTION: Phyllodes tumour (PT) is a rare tumour of the female breast. The tumour clinically and radiologically mimics the features of a fibroadenoma. Ductal carcinoma in situ (DCIS) in the epithelial component of PT is a very rare finding. PRESENTATION OF CASE: We present youngest ever case of a 23-year-old nulliparous woman with high-grade ductal carcinoma in situ arising within a benign phyllodes tumor. Macroscopically, it is a homogeneous tumour with solid components. Microscopically, it features typical leaf-like pattern with hypercellular stroma with high-grade ductal carcinoma in situ. DISCUSSION: To date, eight such rare cases of benign phyllodes tumour with ductal carcinoma in situ have been documented. We report the youngest case known in literature so far. CONCLUSION: As this is a very rare presentation, it poses several challenges in regard to both management and follow-up.