Histology of the breast tissue
Last reviewed: 23.04.2024
All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
When the results of mammography or breast ultrasound show changes that may be of an oncological nature, a sample of pathological tissue tissue is taken - a biopsy is done. The obtained sample is studied by specialists-pathomorphologists and clarifies its cellular structure, that is, the histology of the mammary gland tissue is performed. Histology, as the most important scientific tool of biology and medicine, is the only way to detect abnormal tumor cells.
Therefore, the histology of the breast tumor serves as the most accurate diagnostic method in oncology and helps to choose the most effective way of treatment.
Indications for histology of breast tissue
The main indications for biopsy and histology of breast tissue include the possibility of a malignant pathology when:
- intensive focal or diffuse hyperplasia in various tissues and structures of the mammary glands;
- fibroadenosis, including phylloid fibroadenoma;
- cystic lesions of the mammary glands;
- intrapropate papillomatosis;
- necrosis of tissues (glandular, fibrous, fatty);
- breast cancer, its recurrences and metastases.
The most important signs that give grounds for suspecting the malignancy of the pathological process in the tissues of the mammary glands and resorting to their investigation at the cellular (cytological) level are manifested in the form of interstitial seals (both palpable and fixed on a mammogram or ultrasound); abnormal discharge from the nipple; deformities, discoloration or ulceration of the nipple-areolar zone of the breast; various changes in the skin of the breast; increase in the size of regional lymph nodes, etc.
For more information on the methods and procedure for biopsy behavior, see Breast Biopsy.
Decoding of the histology of the breast: basic indicators
Investigation of the morphology and biochemical features of breast tissue is carried out on the thinnest sections under a light or electron microscope. To increase visualization and more accurate analysis of tissue structures, special histological dyes are used. Due to the phase-contrast, fluorescent, interference and other methods of microscopy, as well as the study of the chemical composition of cells by the method of cytospectrophotometry, the results of histological studies and interpretation of the histology of the mammary gland make it possible to carry out differential diagnosis of tumors - benign and cancerous.
The histology of breast cancer can determine:
- morphological variety of the tumor and its histogenesis;
- degree of malignancy (malignancy);
- hormonal status of the neoplasm;
- degree of spread.
Experts depending on the form of tumor cells distinguish histological forms of malignant neoplasms. If the cells are similar to the brain tissue, then the medullar cancer is determined; if the shape of the cells is tubular, tubular cancer is determined ; at a high content mucin - mucous.
The interpretation of the histology of the breast according to the degree of malignancy or, according to the definition of specialists, the degree of tumor differentiation, is based on the study of the structure of neoplastic cells with the release of mutated cells (cell anaplasia) and the determination of their percentage in relation to healthy cells. The lowest grade of malignancy is the first (GI), the highest is GIV.
The histology of the fibroadenoma of the mammary gland - in the case of a benign pathology - should have a GX score in this indicator, which means that "the degree of malignancy can not be evaluated" (ie, no oncology is detected).
Immunohistochemical method determines the constituent cells of cells, and immunocytochemistry - tissue biomarkers of the membrane receptors of estrogen (ER) and progesterone (PR) and epidermal growth factor (HER2 / neu). Immunofluorescence automated quantitative analysis (AQUA) determines the proliferative activity of the tumor (Ki 67), that is, the intensity of mitosis of its cells.
Deciphering the histology of the mammary gland with respect to steroid hormone markers: positive results for estrogen receptor (ER +) and progesterone (PR +) suggest that the growth of cancer cells depends on these hormones. According to mammologic oncologists, the histology of mammary adenocarcinoma (glandular cancer or ductal carcinoma) with such results is noted in 75-80% of cases in 40-45-year-old women. A hormone-negative cancer (ER- and PR-) is diagnosed in patients after 50-55 years. The presence of these receptors helps to determine both the degree of risk of relapse, and the optimal - hormone treatment of the tumor.
When the results of the histology show the presence of an increased activity of the epidermal growth factor receptors HER2 on the membranes of cancer cells, the so-called HER2-positive cancer is defined, and this cancer is characterized by rapid development.
At results of histology ER-, PR- and HER2- the tumor is called triple negative. Triple negative cancer accounts for about 15% of invasive breast cancer and is the most common type of diagnosis in women with a mutation of the BRCA1 gene.
A high level of Ki-67 is defined in the range of 15-25%, more than 40% is considered a very high indicator and, from a prognostic point of view, means an unfavorable outcome of breast cancer. In addition, the marker of proliferative tumor activity provides information on the effectiveness of preoperative systemic therapy - when comparing its level before and after surgery.
The histology of the breast tissue is the most important method of examining the state of the breast and determining the nature of its pathology.
[6]