Breast Cancer Case
This laboratory exercise is in three parts. First, you will simulate a very common clinical
procedure: the establishment of central venous access. This is routinely done in
emergency procedures or for chemotherapy, for example. Second, you will perform a
mastectomy. The case is written for a woman, but men also can get breast cancer.
Therefore, you can follow this procedure regardless of the gender of your donor. Third, in
preparation for the upcoming labs you will follow an anatomic procedure to remove the
chest plate (don’t try this on a real patient!)
Essential Question:
How does the embryonic migration of cervical somites modify our concept of the body
wall?
Guiding Questions:
 What are the surface landmarks for placing a subclavian line or port?
 What is the arterial supply of the breast?
 What is the innervation of the anterior chest wall?
 What nerves pass through the axilla?
 What important vein passes through the axilla?
 What role do the lymph nodes play in breast cancer, and what are the
implications of their removal?
 How does the organization of the blood vessels and nerves, and especially the
lymph vessels, of the chest wall and axilla guide surgical treatment for invasive
breast cancer?
Central Venous Access: Subclavian vein
You would do this procedure to place a central line for many applications. In today’s case
you would use it for a chemotherapy port, but there are many other applications, e.g.,
emergency delivery of drugs or large volumes of fluid, total parenteral nutrition,
pacemaker leads, etc, etc.
The subclavian vein (sub = deep to; clavian = clavicle: vein deep to the clavicle) drains
the upper limb. It travels through the body wall until it joins with the jugular vein and
enters a thoracic space, the mediastinum, on its way to the heart. Therefore, when
performing this procedure, your needle should always stay in the body wall. What
thoracic cavity will your needle enter if it goes too deep? What organ lies there? What
will be the consequence of this error?
Flash movie cva_intro_1
A muscle separates the subclavian vein from the subclavian artery and nerves to the arm
– the brachial plexus. This muscle is a barrier that protects these structures from injury
by your needle. What is it?
Flash movie cva_intro_2
An important nerve travels on the surface of this muscle. What is it and what is the
consequence of injuring it?
Flash movie cva_intro_3
Besides the veins another type of vessel joins with the subclavian and jugular veins.
What is it, what does it carry and what parts of the body does it drain on the left and
right sides of the body?
Flash movie cva_intro_4
Procedure
1) Place a block under the thoracic region of the back so that the shoulder and head
tilt back.
2) Palpate the acromion process, the sternal notch and he medial third of the clavicle.
Examine the venogram in the radiology resource to see the relationship of the
subclavian vein to these landmarks.
3) Place your index finger in the notch and your thumb under the clavicle. Slide
your thumb laterally along the clavicle until the curvature begins to change. This
should be approximately 1/3 the distance from the notch to the acromion process.
This marks the place where you will insert a needle
4) Draw 1 cc of paint into a syringe with an 18 gauge needle. The syringe should be
parallel to the chest wall. The tip should be just inferior to your thumb and
pointed towards the sternal notch. With the needle, you should feel the underside
of the clavicle as the needle slips underneath. Should your needle pass superior
or inferior to the first rib?
Flash movie cva_4
5) On a patient, you would aspirate until you aspirated blood. Instead, once your
needle has passed under the clavicle for 2-3 cm or so (more for a big patient),
inject the paint. At the end of the lab, you will remove the breast plate and see
what structures you have painted. If you painted the vein you win! If you missed
the subclavian vein you will paint structures that you would not want to injure.
What would these structures be?
Flash movie cva_5
Case (#1-1): Breast Cancer
CC: Breast lump
Use the history and physical and laboratory data to answer the following questions:
During the breast exam, why did the clinician search for palpable axillary and
supraclavicular lymph nodes?
Flash movie hp_1
Do you know any of the risk factors for breast cancer in women? How many can you find
in the history and physical?
Flash movie hp_2
Diagnostic Studies:
You refer SM for screening and diagnostic mammograms, which find a: “~2cm, dense,
irregular, spiculated mass in the RUQ of the R breast. Highly suggestive of malignancy.”
There are no other lesions in either breast.
Look at the normal and abnormal mammograms. Calcifications are not necessarily
indicative of malignancy. Their arrangement, best interpreted by a radiologist, can help
characterize a lesion as likely malignant or benign.
Biopsy: You perform a core needle biopsy of the mass and send the sample to pathology.
Pathology: Invasive ductal carcinoma.
Operative approach:
You have a long discussion about these finding with SM and her husband. Either breastconserving surgery (AKA lumpectomy) or mastectomy would be appropriate, and SM
decides on mastectomy. You will also do a sentinel lymph node biopsy, and progression
to axillary lymph node dissection if the sentinel node is positive. SM has opted for
immediate reconstruction of the breast with a silicone implant, which you coordinate with
your favorite plastic surgeon.
1. Sentinal node dissection (Read but do not perform this procedure)
a. Inject area just to axillary side of tumor with radioactive colloid less than
8 hours pre-op (90 minutes is optimal).
Why is the injection made on the axillary side of the tumor? How will the colloid be
transported to other locations?
Flash movie oa_1a
b. Check for presence of radioactivity over tumor with gamma probe.
c. Follow lymphatic drainage path to hottest “hot spot,” then make a mark on
the skin.
Why would the hot spot be hot?
Flash movie oa_1c
d. Small incision in skin to locate “hot” lymph node, guided by gamma
probe.
e. Remove sentinel node and send to pathology. While waiting for results,
proceed with mastectomy.
What are the implications if cancer is or is not found in the “sentinal” lymph node?
Flash movie oa_1e
f. NOTE: another common technique involves injection of blue dye after
the patient is draped and prepped for surgery. Breast massage for 5
minutes will open up the lymph channels and allow for visualization of the
sentinel node from an axillary incision.
2. Modified Radical Mastectomy
a. Because our patient will be receiving a silicone implant during this
surgery, we do not remove an elliptical piece of skin, as would be done if
no reconstruction were planned.
b. The incision includes the nipple and areola, then proceeds laterally
towards the axilla, in a comma shape. The incision should include the
core biopsy site, to minimize risk of seeding of the needle tract with
malignant tumor cells.
c. Use blunt dissection to separate the breast tissue away from the epidermis,
taking most of the subcutaneous fat out along with the breast.
d. On the deep layer, the specimen includes the deep fascia overlying the
pectoralis major, but not the muscle itself.
Is the mammary gland part of the skin layer or the muscle layer of the chest wall?
Flash movie oa_2d
e. Retract the breast tissue laterally, working from the sternum to the axilla.
f. Once you reach the lateral edge of the pectoralis major muscle, find the
axillary vein and carefully separate the specimen from it.
What region does the axillary vein drain? As the vein travels towards the heart, it
crosses the first rib and changes its name to what?
Flash movie oa_2f
g. Look under the lateral edge of the pectoralis major to see the pectoralis
minor. Visualize the medial nerve to the pectoralis major muscle. It may
pass through the pectoralis minor, or lateral to it.
How would injury to this nerve affect the patient? What motions or functions would be
compromised?
Flash movie oa_2g
h. Visualize the long thoracic nerve and dissect it away from the specimen to
be removed.
What muscle and motion would be compromised if this nerve was injured?
Flash movie oa_2h
i. Visualize the thoracodorsal nerve and dissect it away from the specimen to
be removed.
What muscle and motion would be compromised if this nerve was injured? How does this
muscle, the pectoralis muscles and the seratus anterior differ embryologically and
functionally from other muscles of the body wall?
Flash movie oa_2i
j. Continue retracting the breast specimen until it is free of the latissimus
dorsi muscle and suspensory ligaments.
k. After breast tissue is removed, check the integrity of the long thoracic and
thoracodorsal nerves with a brisk but gentle pinch. (This won’t work on
your donor!)
How would a living patient respond to a pinch of the long thoracic or thoracodorsal
nerve if it was not injured?
Flash movie oa_2i
3. Axillary node dissection (read this procedure and see if you are lucky enough to
find any lymph nodes)
a. Pathology has called to notify you that the sentinel node is positive for
malignancy, so proceed with axillary node dissection.
b. Levels I and II of lymph nodes will be removed and sent to pathology for
staging and hormone-receptor analysis.
What is the goal of collecting these lymph nodes? Why would you want to preserve level
III lymph nodes (the deepest nodes, which have the lowest probability of containing
metastatic disease)?
Flash movie oa_3
4. Reconstruction
a. At this point the plastic surgeon takes over to do the silicone implant. The
implant is inserted deep to the pectoralis major muscle, and the skin
closed.
b. Nipple and areola reconstruction and tattooing to restore natural coloring
will happen later.
Post-operative management:
Because SM is post-menopausal, her tumor is more likely to be hormone-receptor
positive. If this turns out to be the case, she would receive tamoxifen for 5 years. If she
had opted for breast-conserving surgery, she would receive radiation therapy to the R
breast. A pre-menopausal woman with a hormone-receptor-negative tumor would
receive non-hormonal systemic chemotherapy, which would require a subclavian
portocath (a semi-permanent port for delivering chemotherapeutic agents without the
need for repeated injections). This procedure would be a variation of the one you
followed at the beginning of this lab.
Removal of the chest plate
1) Make an incision two finger-breadths above the costal margin. Begin at the
anterior axillary line and extend the incision to just above the xiphosternal
junction and on to the anterior axillary line of the other side. Use retractors to
widen your incision and deepen the incision down to the cartilage and bone.
(Take care to insure that you are superior to the costal margin lest you enter the
abdomen.)
2) Make incisions along the anterior axillary line from your first incision to the
inferior border of the axilla. To preserve the thoracotomy tube you inserted
earlier, make your incision circumvent it on the medial side. Again, carry your
incision down to the rib cage.
3) On the left side, or opposite to the mastectomy, extend your incision to the
intersection of the clavicle and the midclavicular line. From there, proceed along
the inferior margin of the clavicle to the middle of the manubrium. Deepen your
incision down to the rib cage. Which two muscles will be divided? Are they
muscles act on the chest wall or act on the arm?
Flash movie rcp_3
4) On the right side, or same side as the mastectomy, the goal is to preserve the
pectoralis major and minor for future labs. Extend your lateral incision superiorly
taking care not to incise any muscles. Continue the incision medially along the
inferior border of the clavicle to meet the incision from the other side at the mid
point of the manubrium.
5) With the aid of retractors, peel the skin off the pectoralis major. With blunt
dissection, free the muscle from the underlying tissue. It is unnecessary to
preserve the entire muscle. Divide it from its attachments to the rib cage and the
clavicle and reflect it laterally to reveal the pectoralis minor. What is the lateral
attachment of the pectoralis major?
Flash movie rcp_5
6) Similarly, divide the pectoralis minor from its attachment to the ribs and reflect it
superiolaterally. What is the distal attachment of the pectoralis minor?
Flash movie rcp_6
7) You have now completed an incision that encircles the anterior chest wall. Along
this incision, divide the intercostal muscles between ribs and in the first
intercostal space. Try not to cut the pleural lining. Use a rib cutter, wire cutter or
saw to cut the ribs and the cartilage along the costal margin. When using the rib or
wire cutter place a hand as a shield above the cut to prevent bone chips from
flying into one’s eye. Wear eye protection. Your incision along the first
intercostal space, should be extended across the manubrium. The
claviculomanubrial and first costomanubrial joints should be undisturbed.
Additionally, the joint of the second costal cartilage with the angle of Louis
should also remain undisturbed. Which pair of arteries will be divided when you
divide the manubrium? What is their relationship to the arteries that were
divided when you used a chevron incision to divide the rectus abdominis?
Flash movie rcp_7
8) When all the incisions are complete, your goal will be to remove the chest plate,
while preserving the costal pleura. What is the pleural lining? What is the
difference between the visceral, costal, mediastinal, and diaphragmatic pleurae?
Flash movie rcp_8
This may not be possible, because the pleural lining often adheres to the chest plate.
Try to lift the chest plate from a corner and sweep your hand between the plate and
the pleura. If you are successful, share your success with other teams of you learning
society, so that they may appreciate the disposition of the pleural sac. Is the lung
inside or outside the pleural sac? Why or why not?
Flash movie rcp_9
9) Open the pleural sac and insinuate your hand between the lung and the
mediastinum, diaphragm and chest wall. Probe the various recesses. Note that
the visceral pleura is intimately associated with the parenchyma of the lung and
cannot be separated from it. Note that the costal, diaphragmatic and mediastinal
pleura are continuous with one another and that at the hilum of the lung, the
mediastinal pleura reflects off the mediastinum to become continuous with the
visceral pleura. Thus the pleural sac is like a balloon, and the lung is like a fist
that has pushed its way into the balloon.
10) Does the lung and pleural sac extend superior to the clavicle? Can you see any
evidence of the paint that was injected when you placed your “central line”?
What would the presence of paint mean?
Flash movie rcp_10
11) Along the midaxillary line, why does the pleural sac extend more inferiorly (the
costodiaphragmatic recess) than the lung?
Flash movie rcp_11