Friday, March 12, 2021

Breast Cancer Case File

Posted By: Medical Group - 3/12/2021 Post Author : Medical Group Post Date : Friday, March 12, 2021 Post Time : 3/12/2021
Breast Cancer Case File
Eugene C. Toy, MD, Lawrence M. Ross, MD, PhD, Han Zhang, MD, Cristo Papasakelariou, MD, FACOG

CASE 12
A 60-year-old woman is noted to have a 2-cm mass in the left breast. The patient’s physician recommends that a core needle biopsy be performed. Tissue analysis by the pathologist under the microscope reveals intraductal carcinoma. The patient is advised by the surgeon to have surgery to remove the primary breast mass in addition to some lymph nodes. The patient undergoes wide excision of the breast mass and lymph node removal.

Which lymph nodes are most likely to be affected?
 What anatomical structure defines the “levels” of lymph nodes?


ANSWER TO CASE 12:

Breast Cancer
Summary: A 60-year-old woman undergoes lumpectomy and lymph node dissection for a 2-cm intraductal carcinoma of the breast.
Most likely lymph nodes affected: Axillary nodes.
Anatomical structure that defines the “levels” of lymph nodes: The pectoralis minor muscle is used to define lymph node levels. Levels 1, 2, and 3 are lateral to, deep to, and medial to the pectoralis minor, respectively.


CLINICAL CORRELATION
This 60-year-old woman had a palpable breast mass. Pathological examination revealed intraductal carcinoma in the core needle biopsy. Risk factors include the patient’s age, and intraductal carcinoma is the most common histological type. The most common treatment plan would be a breast-conserving procedure such as a lumpectomy (excising the malignant mass with some margins) and axillary lymph node dissection. The presence or absence of malignant cells in the axillary lymph nodes is the single most important prognostic factor for survival. Options for nodal staging include level 1 and 2 axillary node dissection versus sentinel node biopsy. The sentinel node(s) represents the node(s) to which primary lymph drainage occurs from a tumor or anatomical site. It is identified by injection of radiotracers and a blue dye at the primary tumor site. Biopsy of the sentinel node(s) results in a smaller incision and decreased trauma to the axilla. However, if the sentinel node(s) is positive for metastatic disease, a complete level 1 and 2 axillary dissection should be performed.

Other physical signs of breast cancer, which this patient did not have, include skin dimpling or retraction, which is formed by the underlying cancer adherent to the fibrous septa of the breast, and the thickened red appearance of peau d’orange, which is caused by the malignant cells proliferating within the lymphatics underlying the skin. A red, warm breast in a non-breast-feeding woman can also represent inflammatory breast cancer due to malignancy within the lymphatic channels of the skin.


APPROACH TO:
The Axillary Lymph Nodes

OBJECTIVES
1. Be able to describe the anatomy of the adult female breast, including the blood and nerve supplies.
2. Be able to list the primary path for lymphatic drainage of the breast and the several subgroups of axillary nodes.
3. Be able to describe the secondary pathways for lymph drainage.


DEFINITIONS
Axilla: Small pyramidal space between the upper lateral chest and the medial
arm, including the blood vessels, nerves, and lymph nodes.
Tail of Spence: A protrusion of mammary tissue into the axilla that sometimes
enlarges premenstrually.
Axillary lymph node dissection: Surgical excision of lymph nodes
of the axilla, usually related to breast cancer for diagnostic and therapeutic reasons.
Peau d’orange: Orange peel appearance of the skin of the breast with edema
and prominent pores secondary to obstruction of lymphatics by a tumor with associated
inflammation.


DISCUSSION
The adult female breast consists of subcutaneous, radially arranged, mammary gland tissue and fat, typically extending from ribs 2 through 6 superiorly to inferiorly and from the sternal border to the midaxillary line (Figure 12-1). The long thoracic

Sagittal section of the breast anatomy

Figure 12-1. Sagittal section of the breast. (Reproduced, with permission, from Lindner HH. Clinical Anatomy. East Norwalk, CT: Appleton & Lange, 1989:202.)

nerve lies close to the midaxillary line. For descriptive purposes, it is divided into quadrants. Each breast is centered by the elevated nipple, which contains the openings of the lactiferous ducts and is composed of circular smooth muscle. Surrounding the nipple is pigmented skin or the areola, which contains the opening of the lubricating sebaceous glands. The radially arranged mammary gland tissue forms 15 to 20 lobes, each drained by a lactiferous duct that has a dilatation called the lactiferous sinus just before its opening onto the nipple. The lobes are irregularly separated by incomplete dense connective tissue septae that attach to the dermis of the overlying skin. These septae, called the suspensory ligaments (of Cooper), are especially well developed in the superior half of the breast. A loose connective tissue layer, the retromammary space, separates the breast components and the pectoral fascia, allowing for some movement. The breast overlies the pectoralis major and the anterior portion of the serratus anterior muscles. A portion of breast tissue typically extends into the axilla as the axillary tail (of Spence). The breast is supplied by branches of the internal thoracic, lateral thoracic, and anterior and posterior intercostal arteries. The breast is innervated by anterior and lateral cutaneous branches of intercostal nerves.

Lymphatic drainage of the breast begins as a subareolar plexus. The majority of lymph drained from the breast (usually quantified at 75 percent) drains to the axillary lymph nodes. The axillary node group is often described as a pyramid, like the axilla, and is typically subdivided into five subgroups: pectoral (anterior), lateral (humeral), posterior (subscapular), central (medial), and apical. Lymph from the axillary nodes typically drains into the inferior deep cervical lymph nodes. However, lymph from the axillary node group may drain into other nodes such as the interpectoral and deltopectoral nodes (Figure 12-2). This is especially true in instances of metastasis because “normal” paths become blocked by the malignancy and alternate routes must be established. The pectoral, humeral, and subscapular nodes are level 1 nodes, whereas the central and apical nodes are level 2 and 3 nodes, respectively.

The medial quadrants of the breast will have lymph drain into the parasternal lymph nodes along the internal thoracic vessels. Some lymph from the inferior quadrants may drain to inferior phrenic nodes.

Lymphatics of the breast anatomy

Figure 12-2. Lymphatics of the breast. (Reproduced, with permission, from Lindner HH. Clinical Anatomy. East Norwalk, CT: Appleton & Lange, 1989:205.)


COMPREHENSION QUESTIONS

12.1 A 45-year-old woman is noted to have a 1.5-cm breast cancer located in the upper inner quadrant of the right breast. Which of the following lymph nodes is most likely to be affected?
A. Level 1 axillary node
B. Level 2 axillary node
C. Level 3 axially node
D. Parasternal node
E. Inferior phrenic node

12.2 A physician is performing a breast examination. In addition to the breast tissue on the chest, what other region is critical to complete the palpation of mammary tissue?
A. Supraclavicular region
B. Subclavicular region
C. Axillary region
D. Parasternal region

12.3 A 24-year-old woman has vaginally delivered an infant 2 days ago. She complains of breast engorgement and swelling in regions at about the level of the umbilicus and at the lateral abdomen. There seems to be some leaking from these areas of swelling. Which of the following is the most likely diagnosis?
A. Bilateral lipoma
B. Accessory breast tissue
C. Ascites
D. Cutaneous malignancy

12.4 A 52-year-old woman undergoes surgery and finds that she cannot abduct her left arm past 90 degrees. Also, on examination, her left scapula is abnormally prominent. Which surgery is most likely responsible for the patient’s condition?
A. Left lumpectomy and sentinel node biopsy
B. Left radical mastectomy
C. Left carotid artery endarterectomy
D. Splenectomy


ANSWERS

12.1 D. Cancers located in the medial breast usually drain to the parasternal nodes.
12.2 C. The tail of Spence is located in the axillary area and contains mammary tissue.
12.3 B. These areas likely are accessory breast tissue. The “milk line” extends from the axilla to the groin area, and accessory mammary tissue may be present anywhere along this line.
12.4 B. The patient likely has an injury to the left long thoracic nerve, and the deficits resulting from weakness to the left serratus anterior muscle. Injury to the long thoracic nerve leads to inability to abduct the arm past 90 degrees, and also the appearance of a “winged scapula.” A radical mastectomy is the most likely surgery to lead to injury to the long thoracic nerve, particularly in the axillary region. A sentinel node biopsy is a less extensive surgery and not as likely to injure this nerve.


ANATOMY PEARLS
The breast is a subcutaneous structure composed of 15 to 20 lobes of mammary gland tissue and fat and typically extends into the axilla as the axillary tail.
 The breast extends from ribs 2 through 6 and from the sternal border to the midaxillary line. This places the lateral thoracic nerve at risk during surgery.
 The suspensory ligaments of the breast are attached to the dermis of the skin.
 The majority of lymph from the breast drains to the axillary lymph nodes, with secondary drainage to the parasternal and inferior phrenic nodes.

References

Gilroy AM, MacPherson BR, Ross LM. Atlas of Anatomy, 2nd ed. New York, NY: Thieme Medical Publishers; 2012:72−73. 

Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 7th ed. Baltimore, MD: Lippincott Williams & Wilkins; 2014:98−101, 104−106. 

Netter FH. Atlas of Human Anatomy, 6th ed. Philadelphia, PA: Saunders; 2014: plates 179−182.

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