- The Breast Parenchyma:
The breast is the specialized human tissue
located on the chest between the pectoralis
muscle, i.e. the superficial fascia and the
subcutaneous tissue, i.e. right beneath the skin.
- The Retromammary Space:
The breast rests on a rich vascular and lymphatic
network within the pectoralis fascia. This
represents the retromammary space which is
positioned between the deep pectoralis fascia and
the superficial pectoralis fascia.
- The Nipple-Areolar
Complex: The Nipple-Areolar
complex is the center of the breast. It is the
end portion of the largest lactiferous duct.
The Microscopic Anatomy:
The microscopic anatomy is best visualized by
analyzing the lactiferous complex. The breast is a milk
producing organ and its microscopic anatomy is based on
this function.
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- The Lobules: The
lobules, also called the lobular units,
are responsible for the production of
milk.
- The Ductal System: The
milk is collected by distal lactiferous
ducts or acini which merge into minor and
then major lactiferous ducts. In most
instances, these empty into the major
duct or sinus which ends in the nipple.
The ductal system has a ductal
epithelium surrounded by a
myo-epithelium. This ductal epithelium is
responsible for the propulsion of milk
through the ductal system as it has
contractile capabilities. This ductal
system is sealed and surrounded by an
uninterrupted basement membrane.
- The Stroma: This
interlobular tissue, also referred to as
connective tissue, contains capillaries
and other specialized cells.
- Cooper's Ligaments:
These are dense strands of fascia found
throughout the entire breast which end on
the skin itself.
- The Basement Membrane of the
Ductal System: It is essential
to visualize the basement membrane in the
microscopic analysis of a malignant
breast tumor. This will assist in the
assessment as to whether a tumor is
"in situ" (has not grown
through the basement membrane) or
"invasive" (has grown through
the basement membrane).
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The microscopic anatomy of the breast
demonstrates why most breast cancers are ductal or
lobular in origin.
Age Dependant Anatomical
Changes of the Breast:
With age, the breast tissue will change. In a
young woman, the breast tissue is dense and
parenchyma rich. As the woman ages, the fat content
of the breast tissue will increase. This explains the
overall aspect of the breast, as it will begin to
droop. The increased fat content of the breast in
older patients accounts for the higher quality of
their mammograms (increased fat content equals
increased image quality).
Pathology Dependant
Anatomical Changes:
- Peau d'Orange: From the French
term, orange skin, this identifies a malignant
obstruction of the superficial lymphatic
channels.
- Skin Retraction: Skin or
Cooper's ligament pulled in by a malignant
lesion.
- Nipple Inversion: Inward
retraction of the nipple by a malignant ductal
lesion.
- Breast Abscess: Fluctuant,
purulent collection within the breast parenchyma
- Mondor's Disease:
Thrombophlebitis of a superficial vein, usually
by a nonmalignant lesion
- Inflammatory Breast Carcinoma:
Malignant invasion of the superficial skin
lymphatic channels seen in advanced breast
cancer.
- Gynecomastia: This is an
activation and hypertrophy of the breast tissue
in men. It can occur frequently in young men
(pubertal hypertrophy) and in older men. It can
also be caused by numerous medications and
hormones.
Changes Secondary to Breast
Augmentation Surgery
All surgeons should be familiar with the pathology
generated by the placement of breast implants during
augmentation mammoplasty. Earlier augmentation
mammoplasty techniques placed the implants behind the
skin or breast parenchyma. Newer techniques are
placing it behind the pectoralis major muscle.
The anatomy of the axilla or the axillary basin
is important to all oncologic surgeons as it represents
the principal lymphatic drainage region of the breast.
Lymphatic metastasis from a malignant breast lesion will
most often occur in this region. For inner quadrant
lesions, it can occur in the internal mammary chain.
Lymphatic metastasis can also be present in the
supraclavicular nodes.
The surgeon should have an extensive knowledge of the
anatomy of the axilla and its contents in order to
perform a safe, precise and appropriate axillary
dissection.
The lymph node bearing area has been divided into
three axillary regions:
- Level I: Lymph nodes lateral and
inferior to the pectoralis minor muscle
- Level II: Lymph nodes under the
pectoralis minor muscle
- Level III: Lymph nodes under and
deep to the pectoralis minor muscle
Most axillary dissections include lymph nodes from
Level I and II. In order to remove these lymph nodes with
minimal morbidity, several structures will have to be
identified unequivocally. They are as follow:
- The lateral border of the Pectoralis
Minor and Major muscle
- The Latissimus Dorsi Muscle
- The Axillary Vein
- The Long Thoracic Nerve which
innervates the Serratus Anterior Muscle
- The Thoraco-Dorsal Nerve which
innervates the Latissimus Dorsi Muscle
- The Intercostal Brachial Nerve
which is a sensory nerve for the inferior aspect
of the arm and the posterior aspect of the axilla
- The Lateral Pectoral Nerve which
innervates portions of the pectoralis muscle
 CLICK
TO VIEW THE TECHNIQUE: MASTECTOMY
CLICK
TO VIEW THE CHAPTER: BREAST IMPLANTS PATHOLOGY
CLICK
TO VIEW THE TECHNIQUE: AXILLARY DISSECTION
CLICK TO VIEW THE TECHNIQUE:
SENTINEL LYMPHADENECTOMY
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