12 - Breast Pathology Flashcards
What does normal breast tissue look like histologically and what are some physiological changes?
- Dual layer of epithelium: cuboidal and myoepithelial
- Menarche causes increase number of lobules and increased interlobular stroma
- After ovulation cell proliferation and stromal oedema
- Pregnancy causes increase in size and number of lobules, decrease in stroma
What happens to breast tissue as we get older?
- Terminal duct lobular units decrease in number and size
- Interlobular stroma replaced by adipose tissue so mammograms are easier to interpret as less dense and palpation easier
What breast conditions cause a palpable mass and when is this worrying?
- Normal nodularity before menstruation
- Invasive carcinomas
- Fibroadenomas
- Cysts
Worry if hard, craggy, fixed or rapidly increasing in size
What breast conditions cause mammographic abnormalities?
- Densities: invasive carcinomas, fibroadenomas, cysts
- Calcifications: ductal carcinoma in situ (DCIS) and benign tissues
Who is eligible for the breast screening programme in the UK and what are the challenges with this programme?
- Women between 47 and 73 every 3 years
- Very high risk (gene carriers) have annual MRIs and mammograms
- Moderate risk (FH) start screening 40-50
- Many women decline first invite
- Breast screening team are quite old so retiring soon
What are some common lumps in the breast and what age groups do these occur in?
- Fibroadenomas: usually in reproductive age <30 years
- Phyllodes Tumour: in 60’s, can be benign or malignant
- Breast cancer: rare before 25, most people diagnosed at 64. Men are 1% of breast cancer cases
Apart from acute mastitis, what are some other inflammatory conditions that can occur in the breast?
Fat Necrosis
- Can present as mass, skin change or mammographic density
- Can mimic carcinoma clinically and mammographically but usually history of trauma or surgery
What are the histological features of fibrocystic change?
- Cyst formation
- Fibrosis
- Apocrine metaplasia
What are some stromal tumours of the breast?
- Fibroadenoma
- Phyllodes tumour
- Lipoma
- Leiomyoma
- Hamartoma
What are the histological and macroscopic feaures of a fibroadenoma?
- Macroscopically: rubbery, greyish white, mobile
- Histology: mix of stromal and epithelial cells hyperplasia
Can look like carcinoma clinically and mammographically
What is gynaecomastia and what is the general reason for it’s occurence?
- Enlargement of the male breast
- Often seen in puberty and elderly
- Cause by relative decrease in androgen and increase in oestrogen
- No increased risk of cancer but can mimic carcinoma, especially if unilateral
What are some causes of gynaecomastia?
- Neonates due to maternal oestrogen
- Transient puberty
- Klinefelter’s syndrome
- Gonatrophin excess e.g leydig tumours
- Cirrhosis of liver causing oestrogen to not be metabolised
- Drugs: spironolactone, chlorpromazine, alcohol, marijuna, cimetidine, heroin, anabolic steroids
What is the most common type of breast cancer?
- 95% are adenocarcinomas
- 50% occur in the upper outer quadrant
- Other tumours like angiosarcomas are rare
What are some risk factors for breast cancer?
- Geographic influence: higher incidence in US and UK though to be linked to diet, alchol consumption etc
- Previous breast cancer
- Previous radiation exposure, especially as a kid
- Genetics
What are the genes associated with breast cancer?
- BRCA1 and BRCA2: tumour suppressor genes
- Li-Fraumeni Syndrome: p53
- 60-85% lifetime breast cancer risk with this gene and diagnosis 20 years earlier than sporadic cases
- Carriers may undergo prophylatic mastectomy and hysterectomy
How do we classify breast carcinomas?
- Lobular or Ductal
- Invasive or In Situ
What is in situ breast carcinoma and why is DCIS a problem?
- Neoplastic cells limited by basement membrane, myoepithelial cells in tact so cannot metastasise or invafe
- DCIS can show us as calcifications and can spread through ducts and lobules to be very extensive when it breaks through
What does DCIS look like histologically?
Often central comedo necrosis with calcification
What is Paget’s disease of the nipple?
- Unilateral eczematous nipple that can be retracted
- Often a sign of invasive breast cancer behind the nipple
What visible changes can occur to the breast with breast cancer?
- Often axillary lymph node metastases when palpable breast lump
How can invasive breast carcinoma be classfied?
- Invasive ductal carcinoma, no special type: 70-80% of cases with 35-50% 10 year survival
- Invasive lobular carcinoma: 5-15% of cases, similar prognosis
- Other: tubular and mucinous (good prognoses)
What does invasive breast carcinoma look like histologically?
How does breast cancer metastasise and what are the most common sites of metastases?
- Via lymphatics, usually to ipsilateral axillary nodes
- Distant metastases via blood vessels: bones (most common site), lungs, liver, brain
- Invasive lobular carcinoma: odd sites like peritoneum, retroperitoneum, leptomeninges, GI tract, overies, uterus
What factors determine the prognosis of breast cancer?
- In Situ or Invasive
- Tumour grade
- TNM stage
- Histologic subtype (IDC NST has poorer prognosis)
- Molecular classifcation (HER2)
- Gene expression profile
