Lipoma in breast is a benign breast tumor originating from adipose tissue. Usually, the growth of neoplasia is not accompanied by pain or other uncomfortable sensations. Lipoma is detected randomly in the form of a rounded, smooth, elastic, painless volumetric formation. It is diagnosed using ultrasound, mammography and cytological analysis of the material obtained by aspiration biopsy. In the absence of clinical symptoms, dynamic observation is indicated. Large and fast-growing tumors are surgically removed by enucleation, aspiration or sectoral resection.
Meaning
Lipoma in breast can be both an independent disease and a manifestation of lipomatosis — multiple lesions of the body with similar neoplasms, usually of a hereditary nature. Lipomas account for up to 10% of cases of bulky formations detected in the breast. Pathology is more often diagnosed in women after 40 years who have entered the period of involutive changes. In 94-95% of patients, the tumor is located superficially and differs in small size (no more than 2 cm). In patients of reproductive age, fatty neoplasia has a different histological structure, in the menopausal period lipomas with fibrous elements are more often detected.
Causes
The formation of a fatty breast tumor is a polyethological process that can be caused by both internal (genetic, metabolic and hormonal) and external factors. Although experts in the field of mammology have not come to definitive conclusions about the causes of lipomas, several theories of the origin of these neoplasms have been proposed. The main ones are:
- Genetic. Benign overgrowth of adipose tissue in the mammary gland may be a manifestation of hereditary pathology that occurs when the HMG I-C gene and some other chromosome sites are defective. Usually in such cases, lipomas are multiple and serve as one of the clinical manifestations of inherited lipomatoses: Verney-Poten, Gram, Derkum, Roche-Leri syndromes.
- Hormonal. Since the disease is more often detected in women older than 40-45 years, some authors associate its origin with hormonal restructuring occurring at menopausal age. The formation of a lipoma may be the result of a failure of the processes of natural involution of the breast or metabolic menopausal syndrome.
- Exchange. In some patients with lipoma in breast, the concentration of LDL (low-density lipoproteins) in the blood is increased. Poorly penetrating through the vascular endothelium, such fats accumulate in tissues and are encapsulated. The level of LDL increases with inactivity, excessive consumption of animal products, defects in enzyme systems.
- Exogenous. The physiological distribution of adipose tissue cells is controlled by subtle mechanisms of internal self-regulation. Local damaging factors can lead to their failure and local accumulation of fat in the mammary glands: breast injuries, thermal effects (burns, frostbite), incisions during plastic surgery, wearing uncomfortable underwear.
It is most likely that the formation of lipomas in breast tissues occurs when several of these reasons are combined. Some researchers point to the role of compliance with the rules of personal hygiene in the occurrence of pathology of adipose tissue due to the accumulation of so-called sebum produced by the sebaceous glands of the skin. However, this reason is not the leading one in the development of breast adipose glands.
Pathogenesis
The main mechanism of lipoma formation in the mammary glands is tumor-like growth of formation without the occurrence of cell atypia. According to numerous histological studies, in most cases, fatty neoplasia occurs from a single cambial cell, as a result of cloning (reproduction) of which the entire population is formed. Confirmation of this hypothesis of pathogenesis is the lobular structure of many lipomas and the identification of cells with high mitotic activity in them. In addition to adipocytes, such neoplasms may include muscle, vascular and fibrous cellular elements.
Classification
When determining the type of lipoma in breast, its histological composition, localization, and the degree of separation from surrounding tissues are evaluated. The size of neoplasia is usually not taken into account in the classification. The key criterion for attributing a neoplasm to a certain type is the ratio of fatty, fibrous, muscular and vascular elements in its structure. Accordingly, there are:
- Classical lipomas, represented exclusively by fat cells (adipocytes).
- Lipofibromas consisting of adipose and connective tissue with the predominance of the former.
- Fibrolipomas, in which connective tissue elements predominate, but fat is also present.
- Angiolipomas containing a significant number of blood vessels in adipose tissue.
- Myxolipomas, whose fat cells produce mucus that accumulates in the neoplasm.
- Myolipomas that combine fat lobules and smooth muscle fibers in the structure.
Myolipomas and myxolipomas in breast tissue are extremely rare, the main form of the disease are classical lipomas and fibrolipomas. Usually benign fatty neoplasia of the mammary glands are single, less often — pairwise symmetrical or multiple. To assess the prognosis and the choice of medical tactics, it is important to determine how the tumor is separated from other tissues and where it is located. Taking into account these criteria , there are:
According to the degree of differentiation:
- Nodular lipomas are well—formed neoplasms with a capsule of connective tissue.
- Diffuse lipomas are rare neoplasms that penetrate into the surrounding adipose tissue.
By localization:
- Subcutaneous lipomas that do not penetrate the parenchyma of the breast.
- Intramammary lipomas localized between the lobules of the breast.
- Deep lipomas located behind the mammary gland.
Symptoms
Usually, the slow growth of lipomas is not accompanied by pain and discomfort, so the neoplasm is accidentally independently detected by a woman when she reaches the size of 1.5-2 cm or is detected during a preventive breast examination. Extremely rarely, neoplasia causes a cosmetic defect due to the achievement of large sizes — up to 5 cm or more in diameter. The largest of the lipomas found had a diameter of 12 cm and weighed about 500 g. Pain occurs only with deep volumetric formations that can grow into the fascia and fibers of the underlying pectoral muscle. Lipomas are often located subcutaneously in the upper quadrant of one or both breast glands.
When probing, the fatty tumor is painless, has a round or oval shape, smooth surface, clear contours, soft-elastic consistency. If mucus and blood vessels are present in the neoplasia, it is palpated as a dough-like or jelly-like node. Lipofibromas and fibrolipomas are more dense. With a lobular structure of the neoplasm, the skin above it can stretch, due to which there is a slight relief in the form of indentations (depressions). Subcutaneous types of lipomas are well displaced in relation to breast tissues, intramammary ones are less mobile, deep and diffuse tumors can hardly be probed.
Complications
Usually lipoma in breast cause only cosmetic inconvenience. There are no confirmed statistical data on the frequent malignancy of such neoplasms – it is believed that fat cells are little inclined to degenerate into liposarcoma. The risk increases in cases where neoplasia is large and regularly exposed to traumatic effects. Neoplasms with connective tissue in their composition are sometimes prone to calcification, while painful sensations may occur due to compaction and pressure on nerve fibers. One of the rare complications of lipomas is their suppuration or necrosis due to a violation of blood supply.
Diagnostics
Since lipoma in breast has no specific symptoms, instrumental and laboratory studies become the main diagnostic methods. With their help, it is possible to accurately determine the localization of neoplasia, its size, shape and histological structure. This allows you to exclude other types of neoplasms and choose the optimal medical tactics. For diagnosis , the most informative:
- Breast ultrasound. The formation has clear contours, is iso- or hyperechoic. Increased tissue density is characteristic of neoplasia with a fibrous component.
- Mammography. In the image, the lipoma is represented by an X-ray transparent (gray) formation with a clear contour and a radiopaque capsule. Diffuse tumors are difficult to detect by this method.
- Puncture biopsy of the breast. The most reliable way to accurately determine the composition of neoplasia. Usually, the material for cytological examination is obtained by aspiration method.
Differential diagnosis of lipoma is performed with nodular forms of mastopathy, fibroadenomas and other benign tumors of the mammary glands, breast cancer, liposarcoma, involution of the mammary glands according to the lipo-fibrous or fibrocystic type. If necessary, an MRI, CT scan, a study of the level of blood cancer markers (glycoprotein CA 15-3, etc.) are additionally prescribed. An oncologist-mammologist may be involved in the diagnosis.
Treatment
In the vast majority of cases, with a confirmed diagnosis of benign lipoma, dynamic monitoring is recommended for patients with small neoplasms and no pain. Such women 1-2 times a year should be examined by a mammologist and mammography. There are no effective conservative methods of treating fatty tumors. Some experts report the resorption of formations with a diameter of up to 2 cm after the introduction of the glucocorticoid drug diprospan into them. However, this approach has not been widely adopted, and a sufficient array of reliable data on its effectiveness has not yet been accumulated. With accelerated tumor growth, the presence of a gross cosmetic defect, significant pain, surgical removal of neoplasia is recommended. The method of performing the operation and the amount of intervention are determined taking into account the type of lipoma:
- Enucleation of a tumor with a capsule. It is indicated for nodular neoplasms. The exfoliation of neoplasia with its surrounding shell helps to prevent relapse. The intervention is performed in the traditional way using a scalpel, using a laser or radio wave apparatus.
- Aspiration of tumor contents. Adipose tissue is removed through a puncture of the skin of the breast and the capsule of the neoplasm. There are no scars after such an intervention. The disadvantage of the method is the inability to remove the lipoma shell. In the future, this may lead to a recurrence of the tumor process.
- Sectoral breast resection. The operation is indicated for diffuse forms of lipoma, large tumors and suspected malignant neoplasm. Neoplasia is excised within healthy breast tissues according to the contours applied under ultrasound control.
Prognosis and prevention
The prognosis is favorable. The tumor grows very slowly and usually does not cause unpleasant sensations. With properly performed surgical intervention, the disease is not prone to recurrence. Primary prevention of lipoma in breast involves the exclusion of factors contributing to neogenesis, primarily traumatic and other injuries. Rational intake of hormonal drugs, limited implementation of interventions that can provoke dishormonal conditions, sufficient motor activity and a healthy diet are recommended. The task of secondary prevention is the timely detection of the tumor and the exclusion of the malignant nature of the neoplasm.
Literature
- Hartmann LC, Sellers TA, Frost MH, et al. Benign breast disease and the risk of breast cancer. N 1 Engl J Med. 353(3):229-37, 2005 link
- Sabel MS. Overview of benign breast disease. In: Chagpar AB and Chen W, eds. UpToDate. 2 Waltham, MA, UpToDate, 2017
- Laronga C, Tollin S, Mooney B. Breast cysts-clinical manifestations, diagnosis and management. In: Chagpar AB and Chen W, eds. UpToDate. Waltham, MA, UpToDate, 2016
- Kabat GC, Jones JG, Olson N, et al. A multi-center prospective cohort study of benign breast disease and risk of subsequent breast cancer. Cancer Causes Control. 21(6):821-8, 2010 link
- Aroner SA, Collins LC, Connolly JL, et al. Radial scars and subsequent breast cancer risk: 7 results from the Nurses’ Health Studies. Breast Cancer Res Treat. 139(1):277-85, 2013 link
