Wednesday, December 30, 2009

Breast Lump

Anatomy of Breast

The vertical extent of breast is from 2nd-6th ribs inclusive.
The horizontal extent is from the lateral edge of sternum to the mid-axillary line.
2/3rds of the breast overlies the pectoralis major muscle, whereas 1/3 of it over the serratus anterior.
The lower medial quadrant is lying on the external oblique aponeurosis, which separates it from the rectus abdominis.
The breast tissue is separated from the pectoralis major muscle by the pectoral fascia. It's anchored anteriorly to the skin, posteriorly to the pectoral fascia by the cooper's ligament.
The outer prolongation of the gland into the axilla at the level of 3rd rib, is known as the axillary tail of spence. It enters the axilla by piercing the opening in the axillary fascia, known as the foramen of langer, and if it's enlarged, it can be mistaken as a lipoma.

The breast tissue is made up of acini, which forms the lobules, and the aggregations of these lobules made up the lobes. Each of these lobes are drained by a collecting duct, and 10-15 of these ducts drains out to the surface of nipple.

If there's a malignant breast lump, infiltrating the cooper's ligament, it'll lead to dimpling of the skin over breast, due to contraction of the cooper's ligament. If the tumour continues to infiltrate along these cooper's ligament, and now involving the pectoral muscle, it renders it lump non-mobile in a direction parallel to the direction of the pectoral muscle fibers, and mobile in a direction perpendicular to it.

If a tumour infiltrates into the major milk ducts, a subsequent fibrosis is going to cause the nipple to be drawn inwards, and hence leading to nipple retraction.

Peu'd orange, an appearance of orange skin of the skin of breast in infiltrative CA breast, is due to the tumour destruction of the cuticle lymphatics, leading to subsequent lymphostasis and edema, and hence the pits of hair follicles appears depressed from the surrounding skin.

Arterial supply

Lateral thoracic artery (major), a branch of the 2nd part of axillary artery
Perforating cutaneous branch of the interal mammary artery to the 2nd, 3rd, 4th space.
Lateral branches of the 2nd, 3rd, 4th intercostal arteries

Venous drainage

Intercostal veins, axillary veins and internal mammary veins

Lymphatic drainage

The primary lymphatic drainage of breast is the axillary nodes (around 20-30 of them), followed by the internal mammary nodes. Around 75% of the lymphatics of the breast is handled by the axillary nodes, and the remaining 25%, by the internal mammary nodes.

There are 5 groups of axillary nodes, namely the anterior, posterior, lateral, central and apical. By surgical means, they can be classified based on their position in relation with the pectoralis minor muscle.
Nodes located below the lateral border the pectoralis minor -> Level I (anterior, posterior and lateral)
Nodes located behind the pectoralis minor muscle -> Level II (central)
Nodes located above the medial border of pectoralis minor muscle -> Level III (apical)

Lymphatics from the lateral quadrant, some from the medial quadrant drains into the anterior nodes (located behind the lower border of pec. major muscle), and the posteior nodes, which then proceeds to the central nodes, and lastly the apical nodes.

Lymphatics from the right axillary and internal mammary nodes drains into the right subclavian lymphatic duct, whilst lymphatics from the left axillary and internal mammary nodes drains into the thoracic duct, then into the subclavian vein. Both eventually drains into the subclavian vein.

Common presenting problem of the breast

1) Painless lump

Breast cancer
Fibroadenoma
An area of fibroadenosis
Breast cyst

2) Painful lump

An area of fibroadenosis
Breast cyst
Periductal mastitis
Breast abscess
Advanced breast carcinoma

3) Only pain

Cyclical mastalgia
Non-cyclical mastalgia
Very rarely, CA breast

4) Nipple changes

Destruction
Depression (retraction, inversion)
Duplication
Discharge
Deviation
Displacement

Remember these 6 Ds

Different causes of nipple discharge :

Fresh red (blood) -> Duct papilloma
Pinkish (blood + serum) -> CA breast
Greenish/Blackish -> Breast cyst
Creamy, pale yellowish -> Duct ectasia
Whitish -> Lactation

Occasionally, paget's disease of the nipple can be confused with eczema of the breast. To differentiate it :

Paget's disease                       Eczema

Unilateral                                 Bilateral
No vesicles                                With vesicles
Doesn't itch                               Itches
May be associated with lump                No lump
Nipple may not be intact                   Nipple is always intact
Post-menopausal                            Post-lactational

How do you approach in a case of breast lump?

It's by the tripple assessment, which includes history and examination, imaging and Biopsy

1) History 

About the lump : Onset, side, site, duration, progression, initial size, current size

Any pain associated with the lump, and proceed to the details of pain

Is there any skin changes? (dimpling, nodules, ulceration, peu'd orange)
Ask about the onset, duration and progression

Is there any nipple discharge?
Ask about the onset, duration, amount, colour, foul-smelling

Is there any recent nipple retraction?

Is there any lumps felt in the axilla?

Then, proceed to the history of risk factors :

Age of menarche (<11 years old)
Age of menopause (>55 years old)
Age of first child birth (if <30 years old, lesser risk)
Parity index (no. of children)
History of breast feeding and the duration (at least 6 months)
Family history of breast cancer (first degree relatives)
HRT/OCP intake (controversial)
Post-menopausal obesity
Diet - Fatty food predilection

Then, h/o of metastases :

Consitutional -> h/o of weight lost, lost of appetite
Respiratory -> Cough, hemoptysis, dyspnoea
CNS -> Headache, vomiting, diplopia, focal neurological deficits, seizures
Liver -> Jaundice
Musculoskeletal -> Bone pain, pathological fractures

2) Examination

a) Comparison of both breasts

Patient is sitting up, both arms are at her side.
Now observe, any discrepency of size and shape of both breasts?
Is there any differences in between the nipples of both sides?
Is there any visible mass?

Now, ask the patient to lift up both of her arms above head
Observe if there's any accentuation of dimpling or distortion of the breasts?
Observe if both breast are elevated equally (if one is higher than the other, it means that the lump probably has fixed to the pec.major muscle)

Now, ask the patient to bend forwards.
Does both breast moves forwards equally?
If one doesn't move as the patient bend forwards, possibly it has fixed to the chest wall (intercostal muscles or ribs)

Now, examine the affected breast.
On inspection, note :

Size and shape - normal?
Skin over breast - peu'd orange, ulcers, nodules, dimpling, dilated veins
Nipple - retraction, discharge
Visible mass - size, shape, surface
Any ulcers - describe it

On palpation, palpate all 4 quadrants of the breast, including the central area and the axillary tail of spence. Note if there's any lump under headings of :

Number of lumps
Site
Size
Surface
Consistency
Tenderness
Edges
Mobility and fixity

First as the patient's hands are placed over her hips, try moving the lump.
If it's not mobile even when the muscles are relaxed, it means that the lump has infiltrated into the chest wall (skin/intercostal muscles).
If it's infiltrated into the serratus anterior, it'll be the same as infiltration to the chest wall, and noted as stage T4 in TMN staging system.
To test whether it has infiltrated to serratus anterior, ask the patient to push against the wall using both hands, and if renders the lump non-mobile, it means infiltration to serratus anterior has taken place.

If the tumour has already infiltrated into the pectoralis major muscle, the lump is mobile in a direction perpendicular to the muscle fibers, but not in a direction parallel to it. This can be confirmed by asking the patient to press firmly using her hands against her hips, and if the lump now is completely immobile, it means infiltration into the pectoralis major muscle has taken place.

Now, try to feel for any lumps of SC nodes.
Examine the axilla, and note any enlarged nodes in it's numbers, consistency, tenderness, fixity.
Percuss the parasternal region for any dullness.

Repeat the same procedure for the opposite breast and axilla.

Now, examine the abdomen -> hepatomegaly, ascites, PR and PV done (metastatic deposits)
Examine the lungs -> Chest wall tenderness, pleural effusions
Check for any bony tenderness

3) Imaging

For women below age of 40 years old, the imaging of choice is ultrasonography
For women above age of 40 years old, imaging of choice is mammography

4) Biopsy

FNAC
TRU-cut/core-needle biopsy
Incisional biopsy
Excisional biopsy

Further test done :

1) Liver function test - elevation of ALP is suggestive of liver metastases
2) Liver ultrasound - liver metastases
3) Chest X ray - pleural effusions, cannon-ball secondaries, rib erosions
4) CT abdomen and Bone scan (optional - not done in MUAR)

TMN staging of CA breast

Tis - Carcinoma in situ
T0 - No evidence of the presence of primary tumour
Tx - Primary tumour cannot be accessed (may be after BCS/mastectomy)
T1 - Size of tumour is < 2cm, not fixed to muslces
T2 - Size of tumour is 2-5cm, fixed to the muscles
T3 - Size of tumour is >5cm
T4a - Involvement of the chest wall
T4b - Involvement of the skin over breast
T4c - Both T4a and T4b present
T4d - Inflammatory carcinoma

N0 - No evidence of nodal metastases clinically
N1 - Ipsilateral axillary nodes palpable, mobile
N2 - Ipsilateral axillary nodes palpable, immobile
N3a - Both infraclavicular and axillary nodes palpable
N3b - Both internal mammary and axillary nodes palpable
N3c - Both axillary and supraclavicular nodes palpable

M0 - No distant metastases
M1 - Distant metastases present

Hence, the stages are :

Stage I - T1 N0 M0
Stage IIA - T0 N1 M0, or T1 N1 M0, or T2 N0 M0
Stage IIB - T2 N1 M0, or T3 N0 M0
Stage IIIA - T0/T1/T2 N2 M0 or T3 N1/N2 M0
Stage IIIB - T4 N0/N1/N2 M0
Stage IIIC - Any T N3 M0
Stage IV - Any T Any N, M1

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