MEDI7302 Study Guide - Final Guide: Colorectal Adenoma, Stromal Cell, Histology
Benign Breast Disease
Learning
objectives
Describe the anatomy of the breast including blood supply and lymphatic drainage.
Understand the pathology and clinical presentation of benign breast disease
including fibrocystic change, mastitis, gynaecomastia and benign proliferations
Recognize the spectrum of fibroepithelial lesions including fibroadenoma and
Phyllodes tumour
Explain stepwise investigation and management of benign breast conditions
Breast
anatomy
Macroscopic Breast lies between subdermal layer of adipose tissue & superficial
pectoral fascia
Base - it overlies pectoralis major muscle between 2nd-6th ribs
(top-bottom) and between sternal edge to anterior mid-axillary line (left-right); it
overlaps onto serratus anterior and external oblique muscle
Retro-mammary space - the region between breast and pectoralis
major; a thin layer of loose areolar tissue containing lymphatics and small
vessels
Suspensory ligaments of Cooper (fibrous bands) - divides the breast
into lobes; insert perpendicular into the dermis for structural breast support;
start to lax at older age causing pendulous breasts
Microscopic 3 main tissue types
Glandular epithelium
Fibrous stroma and supporting structures
Fat
Age differences
Youth (epithelium + stroma) ---> post-menopausal
(glandular structures replaced with fat)
Structure
Glandular
apparatus
Branching system of ducts
Terminal lobules -> terminal
ductules (or acini) -> multiple branching ducts ->
subareolar ducts -> lactiferous sinuses (10-15) -> nipple
Myoepithelial
cells
Surround entire ductal system
Function - contractile properties to
propel milk
Basement
membrane
Outside epithelial and myoepithelial
layers
Extremely important in
differentiating DCIS in situ (inside basement membrane)
vs invasive cancer (broken through basement
membrane into surrounding stroma)
Blood supply Main supply
Internal thoracic (mammary) artery via 2nd-3rd IC spaces
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[branch off axillary artery]
Lateral thoracic artery [branch off axillary artery]
Perforating branches from intercostal arteries
Pectoral branches of thoracoacromial artery (upper part of breast)
Lymphatics Axillary, internal thoracic (mammary) and supraclavicular LNs
Most of breast drains to axillary LNs
Medial part of breast drains to internal mammary LNs
Axillary LNs is divided into 3 levels
Lateral to pectoralis minor (level I, most lymph nodes)
Posterior to pectoralis minor (level II)
Medial to pectoralis minor (level III)
Nerves Long thoracic
nerve (external
respiratory
nerve of Bell)
Innervation - serratus anterior muscle
Function - fix scapula to chest wall during
shoulder adduction (winged scapula deformity with damage)
Location - close to chest wall, medial side of
axilla
Thoracodorsal
nerve
Innervation - latissimus dorsi muscle
Location - lateral border of axilla
Origin - posterior cord of brachial plexus ->
enters axillary space under axillary vein close to entrance of
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long thoracic nerve -> crosses axilla to medial surface of
latissimus dorsi
Medial pectoral
nerves
Innervation - pectoralis major muscle
Location - inside neurovascular bundle that
wraps around lateral border of pectoralis minor muscle;
axillary vein is supero-posterior to bundle
Sensory
intercostal
brachial
(brachial
cutaneous
nerves)
Innervation - sensory innervation to under-
surface of upper arm + chest wall at posterior margin of
axilla
Location - spans axillary space
Division of these nerves causes anaesthesia
Diagram
Development
and involution
Adolescence
Breast tissue primarily consists of fibrous stroma + scattered ducts
About 12yo, maturation of hormone-dependent tissues for growing breast
occurs via increase in fat deposition, formation of new ducts (branching, elongation),
development of lobular units
Adulthood
Mature or resting breast contains fat, stroma, lactiferous ducts and lobular
units
Cyclic stimulation with hypertrophy accounts for changes in breast
morphology during menses and administration of exogenous hormones
Pregnancy
Adenosis of pregnancy stimulated by estrogen, progesterone and prolactin
leads to milk production and increase in lobular size
Involution during climacterium is characterised by disappearance of lobular
units
Benign breast
problems
Benign lumps in breast Fibrocystic change
Inflammatory - mastitis, abscess, duct ectasia
Benign tumours - fibroadenomas, papillomas, phyllodes,
tubular adenoma
Other - hamartoma, lipoma, haematoma, fat necrosis
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Document Summary
Describe the anatomy of the breast including blood supply and lymphatic drainage. Understand the pathology and clinical presentation of benign breast disease. Breast anatomy including fibrocystic change, mastitis, gynaecomastia and benign proliferations. Recognize the spectrum of fibroepithelial lesions including fibroadenoma and. Explain stepwise investigation and management of benign breast conditions. Breast lies between subdermal layer of adipose tissue & superficial pectoral fascia. Base - it overlies pectoralis major muscle between 2nd-6th ribs (top-bottom) and between sternal edge to anterior mid-axillary line (left-right); it overlaps onto serratus anterior and external oblique muscle. Retro-mammary space - the region between breast and pectoralis major; a thin layer of loose areolar tissue containing lymphatics and small vessels. Suspensory ligaments of cooper (fibrous bands) - divides the breast into lobes; insert perpendicular into the dermis for structural breast support; start to lax at older age causing pendulous breasts. Youth (epithelium + stroma) ---> post-menopausal (glandular structures replaced with fat)
