Specimen source: Left breast biopsy. Diagnosis: Papillary epithelial lesion with ductal ectasia and apocrine metaplasia. The immunostain with the antibody anti-p63 highlights the continuous myoepithelial cells in this papillary epithelial structure, dilated ducts and lobules. The immunostain with Ki67 showed very low (<5%) index. These morphological and immunohistochemical findings are in favor of intraductal benign papillary lesion (intraductal papilloma); however, surgical resection of the lesion is indicated.
Procedure: Left breast lumpectomy/excisional biopsy. Diagnosis: Intraductal papilloma with cystic and apocrine changes. Margins are free. The immunostain showed low Ki67 labeling index (< 5%). The immunostain with the antibody anti-p63 highlights the myoepithelial layer.