– Breast

Breast development

• Breast formed from ectoderm milk streak

• Estrogen – duct development (double layer of columnar cells)

• Progesterone – lobular development

• Prolactin – synergizes estrogen and progesterone

Cyclic changes

• Estrogen – ↑ breast swelling, growth of glandular tissue

• Progesterone – ↑ maturation of glandular tissue; withdrawal causes menses

• FSH, LH surge – cause ovum release

• After menopause, lack of estrogen and progesterone results in atrophy of breast tissue

Nerves

• Long thoracic nerve – innervates serratus anterior; injury results in winged scapula

• Lateral thoracic artery supplies serratus anterior

• Thoracodorsal nerve – innervates latissimus dorsi; injury results in weak arm pull-ups and adduction

• Thoracodorsal artery supplies latissimus dorsi

• Medial pectoral nerve – innervates pectoralis major and pectoralis minor

• Lateral pectoral nerve – pectoralis major only

• Intercostobrachial nerve – lateral cutaneous branch of the 2nd intercostal nerve; provides sensation to medial arm and axilla; encountered just below axillary vein when performing axillary dissection

• Can transect without serious consequences

Branches of internal thoracic artery, intercostal arteries, thoracoacromial artery, and lateral thoracic artery supply breast

Batson’s plexus – valveless vein plexus that allows direct hematogenous metastasis of breast CA to spine

Lymphatic drainage

• 97% is to the axillary nodes

• 2% is to the internal mammary nodes

• Any quadrant can drain to the internal mammary nodes

• Supraclavicular nodes – considered N3 disease

• Primary axillary adenopathy – #1 is lymphoma

Cooper’s ligaments – suspensory ligaments; divide breast into segments

• Breast CA involving these strands can dimple the skin

BENIGN BREAST DISEASE

Abscesses – usually associated with breastfeeding. Staphylococcus aureus most common, strep

• Tx: percutaneous or incision and drainage; discontinue breastfeeding; breast pump, antibiotics

Infectious mastitis – most commonly associated with breastfeeding

• S. aureus most common in nonlactating women can be due to chronic inflammatory diseases (eg actinomyces) or autoimmune disease (eg SLE) → may need to rule out necrotic cancer (need incisional biopsy including the skin)

Periductal mastitis (mammary duct ectasia or plasma cell mastitis)

• Symptoms: noncyclical mastodynia, erythema, nipple retraction, creamy discharge from nipple; can have sterile or infected subareolar abscess

• Risk factors – smoking, nipple piercings

• Biopsy – dilated mammary ducts, inspissated secretions, marked periductal inflammation

• Tx: if typical creamy discharge is present that is not bloody and not associated with nipple retraction, give antibiotics and reassure; if not or if it recurs, need to rule out inflammatory CA (incisional biopsy including the skin)

Galactocele – breast cysts filled with milk; occurs with breastfeeding

• Tx: ranges from aspiration to incision and drainage

Galactorrhea – can be caused by ↑ prolactin (pituitary prolactinoma), OCPs, TCAs, phenothiazines, metoclopramide, alpha-methyl dopa, reserpine

• Is often associated with amenorrhea

Gynecomastia – 2-cm pinch; can be associated with cimetidine, spironolactone, marijuana; idiopathic in most

• Tx: will likely regress; may need to resect if cosmetically deforming or causing social problems

Neonatal breast enlargement – due to circulating maternal estrogens; will regress

Accessory breast tissue (polythelia) – can present in axilla (most common location)

Accessory nipples – can be found from axilla to groin (most common breast anomaly)

Breast asymmetry – common

Breast reduction – ability to lactate frequently compromised

Poland’s syndrome – hypoplasia of chest wall, amastia, hypoplastic shoulder, no pectoralis muscle

Mastodynia – pain in breast; rarely represents breast CA

• Dx: history and breast exam; bilateral mammogram

• Tx: danazol, OCPs, NSAIDs, evening primrose oil, bromocriptine

• Discontinue caffeine, nicotine, methylxanthines

• Cyclic mastodynia – pain before menstrual period; most commonly from fibrocystic disease

• Continuous mastodynia – continuous pain, most commonly represents acute or subacute infection; continuous mastodynia is more refractory to treatment than cyclic mastodynia

Mondor’s disease – superficial vein thrombophlebitis of breast; feels cordlike, can be painful

• Associated with trauma and strenuous exercise

• Usually occurs in lower outer quadrant

• Tx: NSAIDs

Fibrocystic disease

• Lots of types: papillomatosis, sclerosing adenosis, apocrine metaplasia, duct adenosis, epithelial hyperplasia, ductal hyperplasia, and lobular hyperplasia

• Symptoms: breast pain, nipple discharge (usually yellow to brown), lumpy breast tissue that varies with hormonal cycle

• Only cancer risk is atypical ductal or lobular hyperplasia – need to resect these lesions

• Do not need to get negative margins with atypical hyperplasia; just remove all suspicious areas (ie calcifications) that appear on mammogram

Intraductal papilloma

• Most common cause of bloody nipple discharge

• Are usually small, nonpalpable, and close to the nipple

• These lesions are not premalignant → get contrast ductogram to find papilloma, then needle localization

• Tx: subareolar resection of the involved duct and papilloma

Fibroadenoma

• Most common breast lesion in adolescents and young women; 10% multiple

• Usually painless, slow growing, well circumscribed, firm, and rubbery

• Often grows to several cm in size and then stops

• Can change in size with menstrual cycle and can enlarge in pregnancy

• Giant fibromas can be > 5 cm (treatment is the same)

• Prominent fibrous tissue compressing epithelial cells on pathology

• Can have large, coarse calcifications (popcorn lesions) on mammography from degeneration

• In patients < 40 years old:

1) Mass needs to feel clinically benign (firm, rubbery, rolls, not fixed)

2) Ultrasound or mammogram needs to be consistent with fibroadenoma

3) Need FNA or core needle biopsy to show fibroadenoma

• Need all 3 of the above to be able to observe, otherwise need excisional biopsy

• If the fibroadenoma continues to enlarge, need excisional biopsy

• Avoid resection of breast tissue in teenagers and younger children → can affect breast development

• In patients > 40 years old → excisional biopsy to ensure diagnosis

NIPPLE DISCHARGE

Most nipple discharge is benign

All need a history, breast exam, and bilateral mammogram

Try to find the trigger point or mass on exam

Green discharge – usually due to fibrocystic disease

• Tx: if cyclical and nonspontaneous, reassure patient

Bloody discharge – most commonly intraductal papilloma; occasionally ductal CA

• Tx: need ductogram and excision of that ductal area

Serous discharge – worrisome for cancer, especially if coming from only 1 duct or spontaneous

• Tx: excisional biopsy of that ductal area

Spontaneous discharge – no matter what the color or consistency is, this is worrisome for CA → all these patients need excisional biopsy of duct area causing the discharge

Nonspontaneous discharge (occurs only with pressure, tight garments, exercise, etc.)

– not as worrisome but may still need excisional biopsy (eg if bloody)

May have to do a complete subareolar resection if the area above cannot be properly identified (no trigger point or mass felt)

DUCTAL CARCINOMA IN SITU (DCIS)

Malignant cells of the ductal epithelium without invasion of basement membrane

50% get cancer if not resected (ipsilateral breast)

5% get cancer in contralateral breast

Considered a premalignant lesion

Usually not palpable and presents as a cluster of calcifications on mammography

Can have solid, cribriform, papillary, and comedo patterns

• Comedo pattern – most aggressive subtype; has necrotic areas

• High risk for multicentricity, microinvasion, and recurrence

• Tx: simple mastectomy

↑ recurrence risk with comedo type and lesions > 2.5 cm

Tx: Lumpectomy and XRT; need 1 cm margins; No ALND or SLNB; possibly tamoxifen

• Simple mastectomy if high grade (eg comedo type, multicentric, multifocal), if a large tumor not amenable to lumpectomy, or if not able to get good margins; No ALND

LOBULAR CARCINOMA IN SITU (LCIS)

40% get cancer (either breast)