Pathological morphology of breast ductal carcinoma

Intraductal breast carcinoma mostly occurs in small and medium-sized ducts. Cancer cells fill the lumen, and the basement membrane is intact and there is no infiltration. However, this type of cancer involves a wide range of ducts, or at most centrally. It is scattered and histologically, and it was previously believed that this cancer originated from the ductal system, especially the branches of the small ducts. However, the results of recent studies have shown that the initial small foci of intraductal carcinoma mostly begin in the terminal ductal lobular unit. As the number of cancer cells continues to increase, the terminal ducts progressively expand and fuse with each other. Under the stimulation of hormones, the cell components in the more sensitive terminal duct/J lobe unit are far more likely to become cancerous than ductal epithelial cells.

1. The tubules are larger than normal and filled with gray-white tissues. They appear as unclear cords when cut longitudinally and as small nodules when cut transversely. If the intraductal cancer tissue is necrotic, it will appear yellow. Semi-solid soft matter can be squeezed out from the cross section, which is similar to acne on the back skin. This is the so-called acne-type intraductal cancer.

2. Cancer cells are located in the dilated ducts under the microscope, but the basement membrane is intact and there is no infiltration. This is carcinoma in situ. According to its tissue appearance, it can be divided into solid type, comedonal type, cribriform type, low papillary type, etc., and the more common type is mixed intraductal carcinoma.

(1) Solid intratubular carcinoma: The tubes are filled with solid nonpolar cell clusters and have no degree of expansion. The cancer cells are usually small and uniform, and there is generally no necrosis in the central area of ​​the cancer cells.

(2) Comedo-type intraductal carcinoma: The tubes are filled with solid cell clusters, and the central area undergoes significant degeneration and necrosis, becoming a mass of granular eosinophilic, structureless material. The cancer cells in the peripheral area lose their polarity and are generally larger, with round, darkly stained nuclei and common nuclear division images.

(3) Cribriform intraductal carcinoma The cancer cells filling the ducts are medium-sized, forming many circular cavities of varying sizes, resembling sieve holes, hence the name cribriform carcinoma. There is often no necrosis, and even if necrosis occurs, it is mild. The cell size and shape are relatively uniform, and nuclear division is common.

(4) In hypopapillary intraductal carcinoma, the tubules are obviously dilated, and the atypical cells lining them protrude into the cavity in a hypopapillary shape. There is no fibrous stroma in the papilla.