DUCTAL ADENOMA OF THE BREAST - AN IMMUNOHISTOCHEMICAL STUDY OF 5 CASES

The immunohistochemical features of 5 ductal adenomas of the breast we re investigated. The tumours were composed by tubular glands lined by cells with both luminal and basal/myoepithelial immunophenotypes. Tubu les were encircled by an intact basement membrane as demonstrated by s taining for laminin and type IV collagen. Areas of dense fibrosis, a u sual finding in these lesions, stained for fibronectin, type III colla gen and contained vimentin and actin positive spindle cells, consisten t with myofibroblasts. These observations confirm a double epithelial and myoepithelial differentiation in these lesions and seem to support the suggestion that ductal adenomas result from sclerosis of ductal p apillomas.