The two most common types of invasive mammary carcinoma are invasive ductal carcinoma and invasive lobular carcinoma. Other less common types of breast cancer include tubular, mucinous, medullary, and papillary carcinomas of the breast.

Infiltrating or invasive ductal carcinoma is the most common form of invasive breast cancer, representing 80 % of all invasive breast cancers. Physical examination may reveal a spectrum of findings ranging from a benign exam to a palpable mass, skin thickening or dimpling, nipple inversion, or lymphadenopathy. Mammographically, invasive cancer may present in many ways, such as an increased density, architectural distortion, nodularity, a mass or microcalcifications. Grossly, invasive cancers have a wide range of appearances.

Microscopic features which are examined include tubule formation, nuclear pleomorphism, and mitotic activity. Each of the three features is graded from 1 to 3, and a total sum is obtained. A score of 3–5 represents a well differentiated or grade 1 carcinoma. A score of 6–7 represents a moderately differentiated or grade 2 carcinoma. A score of 8–9 represents a poorly differentiated or grade 3 carcinoma. This grading system offers prognostic significance, as patients with grade 1 tumors have significantly better survival than those with grade 2 and grade 3 tumors [11].

Infiltrating lobular carcinoma is the second most common histology, accounting for 10 % of invasive breast cancers. At presentation, invasive lobular carcinoma may be multifocal, and the incidence of bilateral synchronous tumors is as high as 20 % in some series [12]. Physical examination frequently reveals very subtle findings such as induration or a fullness of the breast. The mammographic findings of invasive lobular carcinoma may appear as an asymmetric density, architectural distortion or microcalcifications. It is not uncommon to have subtle or vague findings either on physical exam or imaging, often leading to underestimation of the extent of disease.

Histologic analysis characteristically reveals loosely cohesive neoplastic cells invading the breast stroma in single file, a feature referred to as Indian filing. This growth pattern creates linear strands of tumor cells, which likely accounts for the vague, indeterminate findings seen on exam and imaging studies. Lobular carcinoma is characterized by the loss of a cellular adhesion protein known as epithelial cadherin or E-cadherin. This leads to the loose pattern of cells seen histologically. Staining for E-cadherin is performed to differentiate between ductal and lobular carcinomas. Invasive lobular carcinoma will be negative for E-cadherin or down-regulated in 95 % of cases [13–15]. Invasive ductal carcinoma and ductal carcinoma in situ will characteristically stain positive for E-cadherin [16]. Lobular carcinomas typically express estrogen and progesterone receptors (ER/PR), and usually do not express the human epidermal growth factor receptor protein (HER2/neu) [17].

There are several less common types of breast cancer histologies, and these usually have improved prognosis when compared to ductal carcinomas. Among the most common are tubular, cribriform, mucinous, medullary, and papillary carcinomas. Tubular carcinoma usually has limited metastatic potential and excellent prognosis. Pathologic review demonstrates proliferation of glands and tubules in a single layer without a myoepithelial layer. These tumors generally have low nuclear grade, and when associated with in situ disease, the DCIS is also of low nuclear grade [10]. Invasive cribriform carcinoma also has an excellent prognosis. Histologically, a cribriform or fenestrated growth pattern is seen. It is often observed in conjunction with tumors that have tubular patterns as well. The lack of a myoepithelial layer distinguishes invasive cribriform carcinoma from cribriform DCIS [10]. Mucinous or colloid carcinoma is more commonly seen in patients after the sixth decade [18]. On gross examination these tumor specimens are soft, well-circumscribed masses with a gelatinous consistency. Histologically, tumor cells are seen in clusters within pools of extracellular mucin. These tumors have a favorable prognosis. Some studies report 100 % 10-year survival, compared to 60 % for mixed mucinous and infiltrating ductal tumors [18]. Mucinous carcinomas are traditionally ER and PR positive, and HER2/neu negative. Medullary carcinomas often have an aggressive appearance and are often classified as grade 3 tumors [19]. Most commonly it presents as a palpable mass in the upper outer quadrant of the breast, frequently with palpable axillary lymph nodes. On histologic examination, however, the lymph nodes usually reveal benign reactive changes. Medullary carcinomas are tumors which grow in a characteristic syncitial pattern and often have a surrounding moderate lymphoplasmacytic infiltrate [20]. ER and PR status are usually negative or low (0–30 %), and HER2 is generally negative. Despite these poor prognostic indicators, some studies indicate these cancers have a favorable prognosis [19, 21]. Invasive papillary carcinoma comprises less than 1–2 % of all breast cancers, and is more commonly seen in postmenopausal women. Similar to medullary carcinoma, patients can present with palpable axillary lymphadenopathy, but this is commonly due to benign reactive changes [22].

The staging of invasive breast cancer is based on the TNM classification system of the American Joint Committee on Cancer (AJCC) [23]. The tumor size (T), lymph node status (N), and the presence or absence of distant metastases (M) determines the treatment plan and prognosis of the patient. Stage 1 and 2 tumors are considered early breast cancer, and are usually treated with partial mastectomy followed by whole breast radiation. Axillary lymph node involvement is commonly seen in Stage 3 patients. These cancers are considered locally advanced, and can be considered for neoadjuvant chemotherapy followed by surgery. Patients with Stage 4 breast cancer have distant metastases beyond the breast and regional lymph nodes.

The Halstead radical mastectomy was performed on women with breast cancer for almost 100 years. Removal of the breast, regional lymph nodes, and underlying muscles was the preferred surgical treatment for breast cancer for nearly a decade. This approach was based on the assumption that breast cancers spread in centrifugal fashion, invading adjacent tissue, and then near-by lymph nodes. Complications from the operation were great, and women often suffered from large wounds, lymphedema, and chronic pain. The radical mastectomy underwent numerous modifications as surgeons sought to combine oncologic integrity with less morbid procedures. Patey and Dyson [2] found no difference in overall survival when the pectoralis major muscle was preserved. Madden [24] described preservation of both the pectoralis major and minor muscles, and reported no difference in survival when compared to radical mastectomy. In 1964 Crile [25] recommended excision of the axillary lymph nodes only when they appeared to be grossly involved. In 1991 Toth and Lampert [26] were the first surgeons to describe skin-sparing mastectomy. Preservation of the skin allows for improved reconstruction techniques and better cosmetic result. Retrospective studies comparing skin-sparing mastectomy to standard mastectomy show no difference in recurrence or overall survival [27, 28]. Today, a wide variety of surgical procedures are performed to treat breast cancer. These include total mastectomy with or without reconstruction, modified radical mastectomy, partial mastectomy, sentinel node biopsy, and axillary lymph node dissection.

Total mastectomy is performed for locally advanced breast cancer or diffuse disease. Examples of diffuse disease include muticentric tumors or wide-spread DCIS. Total mastectomy is also performed for inflammatory breast cancer. Women with large tumor to breast ratio may require a mastectomy. A comprehensive review of breast imaging and preoperative image-guided biopsies are essential in all patients with breast cancer [29]. Consultation with a plastic surgeon prior to mastectomy will help determine a patient’s appropriate type of reconstruction. Laboratory work-up should include complete blood count, chemistry, liver function panel, and alkaline phospatase level. Staging work-up is reserved for patients who present as clinical stage 3 or for symptomatic patients whose complaints may indicate systemic metastasis. Staging work-up includes CT scan of the chest, abdomen, and pelvis, along with bone scan.

If a patient is not an appropriate candidate for reconstruction, total mastectomy is performed by making a large skin ellipse around the nipple-areola complex. A skin-sparing approach is used for patients who are undergoing reconstruction. This incision can be extended medially or laterally to improve exposure during the procedure or allow greater access to the axilla during a dissection. The incision is deepened through the dermis and subcutaneous tissue, and an avascular plane between the overlying skin and underlying gland is identified. Mastectomy flaps can be created with sharp dissection using a scalpel or scissors, or with electrocautery. The plane is followed to the borders of the breast, while attempting to remove all breast parenchyma. The breast is dissected to the anatomic borders of the breast: the sternum medially, the clavicle superiorly, the latissimus muscle laterally, and the inframammary fold or rectus sheath insertion inferiorly. The result is a well-vascularized skin flap. Careful hemostasis is achieved and drains are placed prior to closing the wound. One should try to avoid leaving redundant skin on the chest wall, as a smooth, even surface facilitates wearing of breast prosthesis in a more comfortable fashion. The gland is excised off the chest wall, taking care to include the pectoralis major fascia with the specimen. The breast is handled gently throughout the operation and aggressive manipulation of tissue should be avoided. The specimen is oriented with sutures to help aid pathologic margin analysis. Palpation of the mastectomy flaps should be followed with excision of any additional suspicious tissue.

Recently, surgeons have embarked on nipple-sparing mastectomy and nipple and areola-sparing mastectomy. When performing these procedures, intraoperative analysis of the ductal tissue in the nipple can be performed. There are several methods to achieving this goal. One method involves gently inverting the nipple by the surgeon’s forefinger and the ductal tissue is then sharply dissected from the skin. Another method is to sharply dissect the plane deep to the nipple and evaluate this tissue intraoperatively. Some surgeons will place a marker on the nipple bed for orientation purposes for the pathologist. Simmons and colleagues [30] reported on a series of nipple- and areola-sparing mastectomies. In their series, they found a nipple involvement rate of 10 %. Laronga et al. [31] reported a 3 % nipple involvement rate. If intraoperative analysis of the ductal tissue in the nipple is performed and the tissue is found to contain a malignancy, subsequent resection of the nipple-areola complex (NAC) is mandatory. In a retrospective study evaluating 353 nipple-sparing mastectomies, the NAC was preserved in 96.7 % of cases performed [32]. Few patients will retain sensation of the nipple, and both partial and complete nipple loss can be seen. Sacchini [33] published a review of 192 nipple-sparing procedures with a median of 24.6 month follow-up. No patients had involvement of the NAC on pathologic review. Nipple loss in this series was 11 %. Two patients had a local recurrence, but neither recurrence was in the NAC. Careful patient selection remains the key aspect in performing these operations.