Invasive Cribriform Carcinoma Arising in Malignant Phyllodes Tumor of Breast: A Case Report

Phyllodes tumor is an uncommon fibroepithelial neoplasm of the breast. And it is characterized by expanded stroma with increased cellularity and elongated epithelium-lined clefts. Mammary carcinomas within phyllodes tumors have been rarely reported. To date, however, no reports have described the invasive cribriform carcinoma arising in malignant phyllodes tumor. Here, we report a 62-year-old woman who presented with a large breast mass. Microscopically, the mass was a typical malignant phyllodes tumor showing well developed leaf-like architecture and stromal overgrowth with high cellularity and nuclear pleomorphism. In a portion of the tumor, however, the epithelial component showed a cribriform pattern of proliferation in the absence of myoepithelial cells, suggestive of the invasive cribriform carcinoma. To our knowledge, this is rare and it is difficult to make a differential diagnosis of it. Here, we report our case with a review of literatures.