The cause of<unk>  is unknown (idiopathic). A connection between<unk> s and reproductive hormones has been suggested which may explain why they present themselves during reproductive years, increase in size during pregnancy, and regress post-menopause. Higher intake of fruits and vegetables, higher number of live births, lower use of oral contraceptives and moderate exercise are associated with lower frequency of<unk> s. Pathology Macroscopic view of<unk>  of the breast Closeup of a<unk>  of the breast Cytology The diagnostic findings on needle biopsy consist of abundant stromal cells, which appear as bare bipolar nuclei, throughout the aspirate; sheets of<unk> irly uniform-size epithelial cells that are typically arranged in either an antler-like pattern or a honeycomb pattern. These epithelial sheets tend to show typical metachromatic blue on Diff-Quik staining. Foam cells and apocrine cells may also be seen, although these are less diagnostic features. The gallery images below demonstrate these features. Cellular<unk> , also known as juvenile<unk> , is a variant type of<unk>  with increased stromal cellularity. Macroscopic Approximately 90% of<unk> s are less than 3 cm in diameter. However, these tumors have the potential to grow reaching a remarkable size, particularly in young individuals. The tumor is round or ovoid, elastic, and nodular, and has a smooth surface. The cut surface usually appears homogenous and firm, and is grey-white or tan in colour. The pericanalicular type (hard) has a whorly appearance with a complete capsule, while the intracanalicular type (soft) has an incomplete capsule. Microscopic<unk>  of the breast is a benign tumor composed of a biplastic proliferation of both stromal and epithelial components. This biplasia can be arranged in two growth patterns: pericanalicular (stromal proliferation around epithelial structures) and intracanalicular (stromal proliferation compressing the epithelial structures into clefts). These tumors characteristically display hypovascular stroma compared to malignant neoplasms. Furthermore, the epithelial proliferation appears in a single terminal ductal unit and describes duct-like spaces surrounded by a fibroblastic stroma. The basement membrane is intact.
Fibroadenoma
Phyllodes tumor
Intraductal papilloma
Ductal carcinoma in situ
Carcinoma ex pleomorphic adenoma
Invasive lobular carcinoma
Atypical ductal hyperplasia
Lobular carcinoma in situ