Histo: Breast pathology Flashcards
What are the three components of investigating breast disease?
- Clinical examination
- Imaging (ultrasound, mammography or MRI)
- Pathology (cytopathology and/or histopathology)
Outline the coding used by cytopathologists when assessing breast aspirates.
- C1 = inadequate
- C2 = benign
- C3 = atypia, probably benign
- C4 = suspicious of malignancy
- C5 = malignant
What is the gold standard for diagnosing breast cancer?
Histopathology
NOTE: 24-hour turnaround time
Describe the appearance of normal breast histology.
- Glandular tissue will be stained purple with pink stroma around it
- The duct and extralobular terminal duct are together referred to as the terminal duct lobular unit (TDLU)
- Myoepithelial cells will be seen around the outside of the epithelial cells - they help pump milk
Define duct ectasia. Describe its presentation.
- Inflammation and dilatation of large breast ducts.
- Typically presents with a breast lump and nipple discharge.
Describe the histology of duct ectasia.
- The duct will be distended and full of proteinaceous material
- Foamy macrophages will also be present
Define acute mastitis.
Acute inflammation of the breast.
Which group of women tend to be affected by acute mastitis?
Often seen in lactating women due to cracked skin and stasis of breast milk.
Which organism is usually responsible for acute mastitis?
Staphylococci
Describe the cytological appearance of acute mastitis.
Lots of neutrophils
Define fat necrosis.
Inflammatory reaction to damaged adipose tissue
Describe the cytological appearance of fat necrosis.
Fat cells surrounded by macrophages.
Define fibrocystic disease.
- A group of alterations in the breast which reflect normal, albeit exaggerated, responses to hormonal influences
- On histology, the ducts are usually dilated and calcified
Define fibroadenoma.
Benign fibroepithelial neoplasm of the breast.
Describe the histology of fibroadenoma.
Consists of lots of glandular and stromal cells.
Define Phyllodes tumour.
A group of potentially aggressive fibroepithelial neoplasms of the breast.
NOTE: the majority are benign
Describe the histology of Phyllodes tumours.
- Cells do not form uniform layers
- Whether it is benign or malignant depends on the cellularity of the stroma
Define intraductal papilloma.
A benign papillary tumour arising within the duct system of the breast.
What are the two different types of intraductal papilloma?
- Peripheral papilloma - arises in small terminal ductules
- Central papilloma - arises in large lactiferous ductules
How do intraductal papillomas present?
- Central papillomas present with nipple discharge
- Peripheral papillomas usually remain clinically silent
Describe the histology of intraductal papillomas.
- Histology will show a large dilated duct with a polypoid mass in the middle
- The mass tends to have a fibrovascular core
What is a radial scar?
A benign sclerosing lesion characterised by a central zone of scarring surrounded by a radiating zone of proliferating glandular tissue
What pathological phenomenon is thought to be responsible for the formation of radial scars?
Exuberant reparative phenomenon in response to areas of tissue damage in the breast
How do radial scars present?
Seen as stellate masses on mammograms
Describe the histological appearance of radial scars.
Central stellate area with proliferation of ducts and acini in the periphery
Define proliferative breast disease.
A diverse group of intraductal proliferative lesions of the breast associated with an increased risk of subsequent development of invasive breast cancer
Describe the presentation of proliferative breast disease.
Microscopic lesions that usually produce no symptoms
Describe the appearance of usual epithelial hyperplasia.
Irregular lumens
What is flat epithelial atypia/atypical ductal hyperplasia?
- May be the earliest precursor to low grade DCIS
- There are multiple layers of epithelial cells and the lumens become more regular
What is in situ lobular neoplasia?
A solid proliferation of cells within the acinus
What is ductal carcinoma in situ?
A neoplastic intraductal epithelial proliferation in the breast that has not breached the basement membrane
Describe the histological appearance of low grade DCIS.
- Lumens are compact and regular (cribriform (punch out) appearance)
- Rapid death and proliferation of cells leads to calcification
Describe the histological appearance of high grade DCIS.
- Cells are large and few lumens left
- Cells are pleomorphic and occlude the duct
List some risk factors for invasive breast carcinoma.
- Early menarche
- Late menopause
- Obesity
- Alcohol
- OCP
- Family history
Describe the two genetic pathways that result in DCIS.
- Low grade - arise from low grade DCIS or in situ lobular neoplasia and show 16q loss
- High grade - arise from high grade DCIS and show complex karyotypes with unbalanced chromosomal aberrations
Describe the histological appearance of:
- Invasive ductal carcinoma
- Invasive lobular carcinoma
- Invasive tubular carcinoma
- Invasive mucinous carcinoma
- Invasive ductal carcinoma = cells are plaeomorphic and have large nuclei
- Invasive lobular carcinoma = cells have a linear arrangement and are monomorphic. NOTE: cords of cells are sometimes referred to as ‘Indian File’ pattern
- Invasive tubular carcinoma = elongated tubules of cancer cells invade the stroma
- Invasive mucinous carcinoma = lots of ‘empty’ spaces containing mucin
Describe the histological appearance of Basal-like carcinoma.
- Sheets of markedly atypical cells with a prominent lymphocytic infiltrate
- Central necrosis is common
Describe the immunohistochemistry findings in Basal-like carcinoma.
Positive for basal cytokeratins (CK5/6 and CK14)
NOTE: basal-like carcinoma is associated with BRCA mutations
Which histological grading system is used for invasive breast carcinoma?
Nottingham modification of the Blood-Richardson system
What is histological grading dependent on?
- Tubule formation
- Nuclear pleomorphism
- Mitotic activity
Which three receptors are all invasive breast cancers assessed for?
- ER
- PR
- Her2
Describe the receptor phenotype of:
- Low grade invasive breast cancer
- High grade invasive breast cancer
- Basal-like carcinoma
-
Low grade invasive breast cancer
- ER/PR positive
- Her2 negative
-
High grade invasive breast cancer
- ER/PR negative
- Her2 positive
-
Basal-like carcinoma
- Triple negative
What is the most important prognostic factor in invasive breast cancer?
Status of axillary lymph nodes
Which age group is screened in the NHS breast screening programme?
47-73 year olds (every 3 years)
Outline the coding of biopsies for suspicious breast lumps.
- B1 = normal breast tissue
- B2 = benign abnormality
- B3 = lesion of uncertain malignant potential
- B4 = suspicious of malignancy
- B5 = malignancy (a = DCIS; b = invasive carcinoma)
Define gynaecomastia.
Enlargement of the male breast
Describe the histology of gynaecomastia.
- Epithelial hyperplasia with finger-like projections extending into the duct lumen
- Periductal stroma is often cellular and oedematous
- Similar to fibroadenoma
