neurovascular bundle. The LDMF does not compromise the use of other regional flaps, which can then be used in secondary reconstruction if needed.
Transverse rectus abdominis myocutaneous flap surgery. The transverse rectus abdominis myocutaneous (TRAM) flap surgery is no longer the surgical procedure of choice among reconstructive surgeons because of the risk of hernia and abdominal bulge. In addition, there is a limit of lifting anything over 20 pounds postoperatively. In TRAM flap surgery, fat, muscle, and skin tissue remain attached to the original donor site and vascular supply. The tissue is tunneled beneath the skin to the chest to create a pocket for the implant. Skin transferred as part of the muscle flap will lack sensation. TRAM procedure generally uses abdominal tissue, hence, the risk for hernia or abdominal bulge. The TRAM flap technique carries a 5 percent failure rate, in which case the flap dies and must be removed completely. Despite the challenges of TRAM flap, some advantages do exist. Because of the native circulation and ample fat volume, the TRAM flap feels like a natural breast.
During a review of 325 postmastectomy breast reconstructions, researchers assessed three different methods of breast reconstruction: tissue expansion, LDMF, and TRAM flap. Investigators found the aesthetic successes achievable with the three methods to be similar. Some excellent results were managed with each of the techniques. The failure rate after tissue expansion was significantly higher than those observed with the TRAM and latissimus flaps. Tissue expansion also was not as aesthetically successful as other techniques in obese patients. For immediate breast reconstruction, the TRAM flap was the most successful technique. Although tissue expansion has advantages and may not be the best choice for some patients, methods that used autogenous tissue provided more consistent results.
Krishna S. Vyas
University of Kentucky College of Medicine
Shalin Jyotishi
University of Georgia
Henry Vasconez
University of Kentucky College of Medicine
See Also: Breast: Cell Types Composing the Tissue; Breast: Development and Regeneration Potential; Breast: Major Pathologies.
Further Readings
Allen, R. J. and P. Treece. “Deep Inferior Epigastric Perforator Flap for Breast Reconstruction.” Annals of Plastic Surgery, v.32/1 (January 1994).
Gentile, P., C. Di Pasquali, I. Bocchini, M. Floris, T. Eleonora, V. Fiaschetti, R. Floris, and V. Cervelli. “Breast Reconstruction With Autologous Fat Graft Mixed With Platelet-Rich Plasma.” Surgical Innovation, v.20/4 (August 2013).
Palao, R., P. Gómez, and P. Huguet. “Burned Breast Reconstructive Surgery With Integra Dermal Regeneration Template.” British Journal of Plastic Surgery, v.56/3 (April 2003).
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Breast: Major Pathologies
The study of stem cells has become popular in the fields of research and medicine. Preliminary experiments mostly in animal models suggest that understanding the pathology of stem cells and diseases that occur within the breast can lead to treatments for these pathologies.
Breast and Nipple Anatomy
The breasts, medically referred to as mammary glands, are located at the front of the body overlying the pectoralis major muscle. This includes the base of the breast, which is fixed between the second and sixth rib. Breast anatomy is composed of a network of glandular structures, fatty tissue, blood vessels, and lymphatic vessels.
The breast has three structures: skin, subcutaneous tissue, and breast tissue. The average dimension of a breast is 10 to 12 centimeters and has a thickness of 5 to 7 centimeters. It contains hair follicles, sweat glands, and oil glands. The nipple averages 15 to 60 millimeters in dimension and has a circular areola. The nipple is also comprised of oil and sweat glands, and there is a high concentration of sensory nerve endings as well.
Stem Cells in the Breast
Adult stem cells, medically referred to as somatic stem cells (SSC), are located in various organs throughout the body. Somatic stem cells are undifferentiated cells that have the unique ability to divide into two identical daughter cells or to transform into specialized cells. This choice between self-renewal or differentiation is determined by the environment. These rare somatic stem cells are essential to renew and to repair tissues, but the self-renewal properties of somatic stem cells can increase their chances of becoming cancer cells.
Mutations of Stem Cells
When somatic cells replicate and divide, both point and chromosomal mutations accumulate with each additional generation of daughter cells because the replicative machinery commits errors and because of exposure to mutagenic agents. These mutations can have significant influences on cellular birth and death rates depending on the nature of the mutation. When comparing normal somatic cells with mutated somatic cells, it is important to realize that normal somatic cells grow, replicate, and die only when they receive specific signals. However, point or chromosomal mutations can allow somatic stem cells to create their own growth signals, to respond to signals destined to other cells, or to escape signals that cause normal cells to die by a process called apoptosis.
Mutations that increase the growth rate of somatic cells or that allow them to escape normal regulatory signals give them a selective advantage that allows them to outcompete their normal counterparts. As more genetic mutations occur, more functions in the cells can be affected. These malfunctions include disregulation of proto-oncogenes that stimulate cell growth, tumor-suppressor genes that suppress cell growth, and apoptosis genes that control cell death. The cumulative effect of these malfunctions leads to initial tumor formation.
Cancers of the Breast
Breast cancers are classified by two major categories depending on where they originate in the breast. Malignant breast tumors are common in postmenopausal women and arise from mammary duct epithelium or lobular glands. They are usually the result of overexpression of estrogen and progesterone receptors or erb-B2 (or HER-2, an epidermal growth factor receptor). Axillary lymph node involvement is the single most important prognostic factor in breast cancer. Risk factors for malignant breast tumors include increased exposure to estrogen.
The majority of patients with breast cancer have cancer that originated in the milk ducts of the breast. This type of cancer is called ductal carcinoma, and there are two subtypes: invasive and noninvasive. The noninvasive type of ductal carcinoma is named ductal carcinoma in-situ (DCIS). This type of cancer arises from ductal hyperplasia, which fills the ductal lumen and is considered noninvasive because it does not spread to other tissues of the breast. The second type of ductal carcinoma is named invasive ductal carcinoma and is characterized by the spread of the cancer through the walls of the milk ducts into other tissues of the breast. This results in a firm, fibrous, hard mass with sharp margins and small, glandular duct cells. Invasive ductal carcinoma is the most invasive and most common, accounting for over 75% of breast cancers.
The second major category of breast cancers comes from cancers that originate in the lobules of the breast. The lobules are the parts of the breast responsible for lactation, or the production of milk. Cancers of this type are called lobular carcinomas. Similar to ductal carcinoma, lobular carcinoma contains also two subtypes of the cancer: lobular carcinoma in-situ and invasive lobular carcinoma. Invasive lobular carcinoma is similar to invasive ductal carcinoma in that it spreads outside the lobules of the breast into other tissues. It differs, though, in that there is not a lump that is associated with the cancer. Instead of creating a lump, the cancer cells cause the tissues of the breast to thicken.