Carcinomatous cells are seen below the basement membrane of lactiferous ducts. The fibrosis is remarkable and lactiferous ducts are short and severely retracted. Microdochectomy is the surgical removal (excision) of a lactiferous duct. Central duct excision is the surgical removal (excision) of all lactiferous duct under the nipple. However past studies have shown that the lactiferous sinus does not exist. The lobules drain milk through the lactiferous ducts out of the nipples. The lactiferous duct should be normal without any retraction. The majority of breast diseases either originate from lactiferous ducts or are closely related. Lactiferous duct development occurs in females in response to circulating hormones. Lactiferous ducts are lined by a columnar epithelium supported by myoepithelial cells. Each lobule has a "lactiferous duct" that drains into openings in the nipple. Another particular trama cell type are "lactiferous" hyphae (also "lactifers"). Surgery may also damage the lactiferous ducts and the nerves in the nipple-areola area. They are lactiferous, producing latex, which may be milky or watery, coloured or plain. Unlike "Russula", "Lactarius" also have lactiferous, i.e. latex-carrying hyphae in their trama.