Week 8 - FNA Breast Cytopathology Flashcards
Main Aims of the Triple Test
To maximise diagnostic accuracy in breast tissue
To maximise the preoperative diagnosis of cancer
To minimise the proportion of excisional biopsies
To minimise the proportion of benign excisional biopsies
Aim of IAC Standardised Reporting of Breast FNA Biopsy Cytology
Aim was to develop ‘best practice’ guidelines covering;
- indications for breast FNAB cytology
- the FNAB technique, smear making and material handling procedures
- a practical, standardised and reproducible reporting system
- the appropriate ancillary diagnostic and prognostic tests
- correlation with clinical management algorithms
Categories for Reporting FNAB Cytology
Code 1 - Insufficient material
- too sparsely cellular or poorly smeared or fixed
Code 2 - Benign
- cases that have unequivocally benign cytological features which may or may not be dx of a specific benign lesion
Code 3 - Atypical
- the presence of cytological features seen predominantly in benign processes or lesions, but with additional features that are uncommon in benign lesions and may be seen in malignant lesions
Code 4 - Suspicious
- as the presence of some cytomorphological features, usually found in malignancy lesions but with insufficient malignant features, either in number or quality, to make definitive dx of malignancy
Code 5 - Malignant
- unequivocal diagnosis of malignancy, include type whenever possible
Structure of Breast
Prior to puberty the breasts contain a few ducts which are connected to the nipple and open to the external surface
But there are NO glandular structures
Before menstruation commences, lengthening and branching of these ducts occur and the terminal buds appear
This then leads to an increase in fat deposition and connective tissue
With the onset of puberty, further growth takes place and continues until at least the age of 25, unless this is accelerated by the onset of pregnancy
Developmental Abnormalities of the Breast
Failure of breast development
- very rare however in some cases this may be due to ovarian agenesis (Turner’s syndrome)
Accessory nipples
- most common abnormality and can occur anywhere along the ‘milk’ line
Juvenile hypertrophy
- characterised by rapid and disproportionate breast growth during puberty, which may be due to psychological distress and may warrant surgical reduction
Function of Breast
The main function of breast is to produce and express milk
The lobules are the main secretory unit of the breast
Each lobule consists of a variable number of acini, or glands, embedded within loose connective tissue and connecting to the intralobular duct
Each of these acini/glands are composed to 2 main cell types
- epithelial ductal cells
- myoepithelial cells
The intralobular duct connects with the extralobular duct and this together with the lobule makes up the terminal ductal lobular unit
The extralobular ducts within the same area are linked together to form subsegmental ducts which in turn link to form segmental ducts
These drain into lactiferous ducts and sinuses which empty onto the skin surface of the nipple through several small orifices
Benign Cytopathology
Normal epithelial cells
Small cohesive groups
Monolayer sheets
Occasional complete terminal duct-lobular units
Nuclei are oval with regular outlines, 8-10µm diameter
Inconspicuous nucleoli
Evenly dispersed chromatin pattern
Scanty delicate cytoplasm
Oval myoepithelial cells with dense nuclei at periphery of sheets
Naked bipolar (myoepithelial cells) in background of smears
Comparison of Benign Pattern to Low Grade Carcinoma
Benign has lower cell yield
Benign has more cohesive sheets
Benign shows small nuclei with bland chromatin and LGC has darker nuclei also with relatively bland chromatin
Benign shows myoepithelial cells, LGC doesn’t
Benign shows bare oval nuclei, LGC doesn’t (LGC shows single cells with tufts of cytoplasm)
Breast Tissue in Pregnancy and Lactation
Cellular smears
Poorly cohesive mainly dispersed epithelial cells of acinar type
Cells have abundant fragile cytoplasm containing secreting vacuoles and frayed borders
Round vesicular nuclei with central nucleoli
Dirty/lipid background with stripped nuclei containing prominent nucleoli
Single bipolar nuclei are difficult to find
Gynaecomastia Smears
Cellular
Epithelial fragments occur as large/flat/monolayered sheets
Some ‘fingerlike’ projections (similar to that seen in FA)
There is a bimodal pattern of single bare/bipolar nuclei in background
Adipose tissue may be present
Moderate nuclear variation and atypia may be seen
Fibrocystic Change Smear
Cohesive sheets of benign ductal cells arranged in flat honeycomb sheets, no loss of polarity with distinct cell borders
May have cystic bg, may be clean
Bare myoepithelial nuclei present
Apocrine cells
Cystic/foamy macrophages (not as many as benign cyst)
Fat and stroma
Simple Breast Cyst
Complete disappearance of lump following aspiration.
Cystic bg +++
No bare oval nuclei
‘Cyst macrophages’ +++- have abundant delicate vacuolated cytoplasm which may contain pigment
Apocrine epithelial cells - have abundant dense basophilic cytoplasm (MGG), nuclei are round, nuclear size may vary with prominent nucleoli
Nuclear outline is smooth and chromatin pattern is uniform
Inflammatory cells (polymorphs)
Mastitis Smear
Benign bimodal component of non neoplastic epithelium
Cystic bg
Inflammatory cells, chronic/acute
Regenerative epithelial atypia
Histiocytes, epithelioid cells, multinucleated giant cells and plasma cells (granulomatous reaction)
Microorganisms (infectious mastitis)
Fat Necrosis Smear
Normally has previous Hx of recent surgery
Little epithelium
Numerous foamy/cystic macrophages
A granular cystic background
Multinucleated giant cells
Sparse and variable numbers of inflammatory cells
May see anucleate squamous cells
Fibroadenoma Smear
Highly cellular
Epithelial component is regularly arranged in large sheets, may be elongated and branching aggregates
Variable nuclear crowding and overlapping, but nuclei are uniform with a bland chromatin pattern
With 1 or 2 small indistinct nucleoli
Increased bare oval nuclei
Fragments of fibromyxoid stroma (stain magenta on MGG) are present within the background. These have a fibrillary structure with spindled, elongated fibroblastic nuclei
Differentiating Between Epithelial Hyperplasia, Atypical Ductal Hyperplasia and Low Grade DCIS
Epithelial highly cellular, ADH and LG are cellular
All show large cohesive sheets and few single cells
Epithelial shows streaming pattern
All show nuclear crowding and overlapping
Epithelial has absent or mild atypia
ADH and LG have mild to moderate nuclear atypia
Epithelial and ADH have few bare oval nuclei, LG has none
Epithelial and ADH have clean background, LG has necrotic background
Epithelial and ADH can show calcium granules, LG doesn’t
Intraductal Papilloma
Yields minimal fluid but contains highly cellular smears with large aggregates and dispersed cells
Complex folded and branching aggregates with finger-like fragments
Some association with collagenous stromal cores and dense fibrovascular cores
Rows of palisaded/columnar cells indicating papillary or cribriform lesions
May have a background of foamy macrophages and cystic debris
Bare bipolar nuclei are variable and often sparse
Phyllodes Tumour
Phyllodes tumour is a biphasic epithelial/stromal neoplasm of breast
Classified as benign, low grade (borderline) and high grade (malignant), based upon histological features
- invasive growth pattern at tumour periphery define whether a phyllodes is benign, borderline or malignant
- benign phyllodes do not metastasise but may locally recur if incompletely excised.
- high grade phyllodes behave like sarcomas with potential for recurrence and metastasis
- low grade (borderline) neoplasms fall somewhere in between.
