Fibroadenoma Developing Ductal Carcinoma in situ Component, Associated with Separate Invasive Ductal Carcinoma Lesion: A Rare Case Report

Among the fibroepithelial lesions of the breast, fibroadenoma is the most common entity. It is generally present as a mobile lump. Malignancy inside fibroadenoma is very rare, only 0.002% to 0.125% cases are reported which were turned to be malignant. In the present case, a 41-year-old female patient had a history of lumps for 4 years and was previously diagnosed with fibroadenoma. After 4 years of follow-up, it turned to be malignant with a separate tumor nodule outside the fibroepithelial lesion and ductal carcinoma in situ component within it. The unicity of the case is that fibroepithelial lesion shows features of fibroadenoma and phyllodes as well as ductal carcinoma in situ. Most of the axillary lymph nodes also show deposition of tumor cells within it.