Breast cancer pathological classification

Breast cancer is a disease that is the same as other tumors. It has many causes. It may be caused by genetic factors or sex hormone disorders. This disease is more common in women during menopause and can affect the function of their breasts, causing breast pain. It requires timely surgical removal of breast cancer to prevent the spread of the tumor.

[Cause]

Like other malignant tumors, the true cause of breast cancer is still unclear. However, through basic and clinical research, a large number of epidemiological surveys and analyses, it is known that many factors can affect the occurrence and development of breast cancer, and the three pathogenic factors of endocrine, genetic and viral have been studied more extensively and in depth.

1. Sex hormone disorder: Estrogen (especially estradiol) and prolactin have been proven to have carcinogenic effects in animal experiments. Breast cancer mainly occurs in women, especially before and after menopause, women with early menarche and late menopause. When both ovaries are underdeveloped or have been surgically removed, the incidence of breast cancer decreases significantly. In addition, it is also related to corticosteroid metabolism disorders and exogenous estrogen.

2. Genetic factors: For women with a family history of breast cancer, the relative risk of developing the disease is 2.4 and 1.7 before and after menopause, respectively (normal women have a relative risk of 1). Especially for women whose mothers and sisters have bilateral breast cancer before menopause, their chances of developing breast cancer before the age of 40 are greatly increased.

3. The carcinogenicity of the virus has been confirmed in animal experiments. Type B virus-like particles have also been found in human breast milk and breast cancer tissue. However, some people hold a negative attitude, and there is still insufficient epidemiological evidence to confirm it.

Some people also believe that the incidence of breast cancer is closely related to lifestyle, diet, nutrition, calories, obesity, etc.

[Pathological classification]

The morphology of breast cancer tissue is relatively complex, with many types, and often more than two types can exist simultaneously in the same piece of cancer tissue or even in the same section. At present, there is still no unified international and domestic breast cancer pathology classification in practical application. The pathological classification of breast cancer in China is as follows:

1. Non-invasive cancer: refers to the earliest stage of cancer. When the lesions are confined to the mammary ducts or alveoli and have not broken through the basement membrane, it is called non-invasive cancer.

1) Lobular carcinoma in situ: cancer originating from the lobular duct and terminal duct epithelium, accounting for about 1.5% of breast cancer. The cut surface shows a pink, translucent, slightly hard granular area. The lesions are mostly multifocal. The cancer cells are large in size and have consistent morphology, but disordered arrangement. The basement membrane around the duct is intact. Both sides are often affected and the disease develops slowly.

2) Intraductal carcinoma: Carcinoma in situ occurs in the central duct. The lesions may involve a wide range of ducts or appear multi-centric and scattered. The cross-section is granular with gray or light yellow dots, just like acne-like contents in the skin.

2. Early invasive cancer: The development from non-invasive cancer to invasive cancer is a gradual process. During this period, it goes through the early infiltration stage and is divided into two categories according to its different morphologies.

1) Early invasive lobular carcinoma: Lobular carcinoma in situ penetrates the basement membrane and infiltrates into the interstitial tissue of the lobule, but has not yet infiltrated beyond the lobule.

2) Early invasive ductal carcinoma: A small number of cancer cells in ductal carcinoma break through the ductal basement membrane and infiltrate into the interstitium, but the infiltration range is small.

3. Invasive cancer: Cancerous tissue extensively infiltrates into the stroma, forming an image in which various forms of cancerous tissue are mixed with stroma. Invasive carcinoma is further divided into invasive special type carcinoma and invasive non-special type carcinoma. Invasive non-special type carcinoma is further divided into simple carcinoma, scirrhous carcinoma and medullary carcinoma according to the proportion of cancer tissue and stroma.

1) Invasive carcinoma of no special type:

① Simple cancer: more common, accounting for more than half of breast cancer. The parenchyma and interstitial components of cancer tissue are similar, and cancer cells often aggregate into small nests, sheets or thick cords.

② Hard cancer: It accounts for about 10% of all breast cancers and is characterized by less carcinoma and more stroma. It is small in size, hard in texture, porcelain white in cut surface, and the edge of the cancer is crab-foot-like and infiltrates toward the surrounding area.

③ Medullary carcinoma: It accounts for about 10-20% of the total number of breast cancers, with more cancer tissue than stroma. The tumor can reach a huge size, with a grayish white cross-section and often necrosis in the center. According to the different degrees of lymphocyte infiltration in the stroma, it can be divided into two subtypes: those with less lymphocyte infiltration are non-yellow medullary carcinoma, and those with more infiltration are typical medullary carcinoma. The latter has a good prognosis and is often classified as a special type of invasive carcinoma.

2) Invasive special type carcinoma

① Papillary carcinoma: intraductal carcinoma, rarely evolved from intraductal papilloma. It is more common in women aged 50 to 60. The lumps are single or multiple. Some have nipple discharge, mostly bloody, and cancer cells can be found in the discharge smear. The cross section is a brown-red nodule with a brittle texture and pink slough-like or papillary tissue inside. This cancer grows slowly and metastasizes later. When more than half of the cancer parenchyma shows glandular duct-like structures, it can be diagnosed as adenocarcinoma.

②Mucinous adenocarcinoma: also known as colloid carcinoma, less common. The age of onset is old, the growth is slow, the borders are clear, the cross-section is translucent and jelly-like, the cancerous tissue contains abundant mucus, the malignancy is low, and axillary lymph node metastasis is rare.

③ Eczematoid carcinoma: also known as Paget's disease of the breast. The morphological characteristics of this cancer are: eczematous changes in the nipple and areola skin and the appearance of large and characteristic Paget cells in the epidermis. Most of these cancers are combined with intraductal carcinoma and lobular carcinoma in situ, and some are invasive ductal carcinoma.