Cytology Flashcards
How to Make a CellBlock
Centrifuge sample and discard supernatant.
Add plasma and thrombin to form a small pellet
Fix in formalin and then process / embed / cut as per FFPE block
Trouble shoot Histo / Cyto Discordance
1) Double check patient ID and clinical details (right specimen, right patient?)
2) Levels on histology, review original cytology
3) Still discordant?
- discuss at MDM
- consider lesion elsewhere in gynae / GI / GU tract
- repeat biopsy
DDx Unilateral Pleural Effusion
NON NEOPLASTIC
- infection eg. bacterial pneumonia, TB
- PE
- LVF
- Cirrhosis
- Autoimmune / CTD - RA / SLE
NEOPLASTIC
- Mesothelioma
- Lung carcinoma
- Pleural metastases from breast, ovary, GI tract
- Lymphoma (primary e.g. PEL or secondary)
Adeno versus Meso Panel
Adeno (Epithelial):
MOC31, BerEp4, claudin 4
Meso:
WT1, calretinin, D240
BAP1 lost
Homozygous deletion of p16 / CDKN2A by FISH
Explain how you would report this urine cyto using the Paris system
Standardised reporting system based on cytomorphology that stratifies urine specimens into risk groups
- NHGUC
- LGUN (TPS 2.0)
- AUC
- SHGUC
- HGUC
Key point in decision tree = N:C ratio >0.5
Additional features: hyperchromasia, coarse chromatin and irregular nuclear membranes
2 features plus N:C ratio >0.7 - SHGUC or HGUS depending on quantity / number of cells
Reasons for False Negative Results in Cytology
False negative = wrongly stating a disease is absent
(Can divide into specimen problems and pathologist problems)
1) Sampling error
2) Obscuring artefact (blood, inflammation, air drying)
3) Poor preservation of cells / degenerate cells
4) Scarcity of neoplastic cells
5) Misinterpretation / misclassification
Reasons for False Positive Results in Urine Cytology
False positive= wrongly stating a disease is present when it’s not(
(think of benign mimics)
1) Reactive atypia: bladder stones, IDC, chemo / rads
2) Viral cytopathic effect: BK virus
3) Contaminant cells: upper GU tract, gynae tract, via ileal conduit
4) Not urothelial carcinoma!
- other primary bladder: SCC, adeno, SCNEC, paraganglioma
- secondary epithelial: metastasis from breast, prostate, GI, gynae
- non epithelial tumours: melanoma, lymphoma
Causes of False Positives in Thyroid FNA
False positive = stating a disease is present when it’s not
(Think of benign mimics)
1) Inflammation - thyroiditis
2) Hyperplasia - nodular / MNG
3) Benign neoplasms - follicular adenoma, NIFTP, HTT
4) Not thyroid! : parathyroid gland
Causes for False Positives in Effusion Cytology
False Positive = stating a disease is present when it’s not
(Think benign mimics)
1) Misinterpretation of cytologic artefacts from specimen collection and preparation - degenerative nuclear features (hyperchromasia, cytoplasmic vacuolation)
2) Reactive mesothelial cells
3) Mullerian inclusions / endosalpingiosis (peritoneum)
3) Unexpected / unusual findings e.g lymphoma, megakaryocytes from bleeding
How is a Papinicolau stain performed?
Papanicolau stain is a modified H&E stain which is most useful for identifiying nuclear features in cells.
- Fix with Ethanol.
- Nuclear stain = Alum Haematoxylin
- Cytoplasmic stain = mix of two stains Orange G (good for keratin) and Eosin Azure (mix of three dyes)
- Dehydration, clearing, mounting
How do you perform a DQ stain?
The DQ or “Diff Quik” stain is a commerical Rominowsky stain variant used to rapidly stain and differentiate cytology specimens.
- Air dry and fix with ethanol / methanol
- DQ I (pink) = Eosin Y, xanthene + ph Buffer
- DQ II (blue) = Thiazine, methylene blue, azure + pH buffer
- Rinse and admire!
How do you assess adequacy in LBC?
Adequacy = 5000 well preserved and well visualised cells or diagnostic material.
Look at 10 x 40x fields - should have 5 - 10 cells in each.
In NZ: Two LBC systems - Surepath and Thin Prep. Similar principles but slightly different technology / process for each.
ThinPrep gives bigger, thinner circle of cells.
SurePath gives a small, dense circle of cells.
Basic process = cervibroom -> vial with fixative 56 or 24% ethanol.
Vial put into machine (may get agitated), fluid extracted via a filter or via gravitation sediment then cells concentrated and deposited on slide.
Can do HPV genotyping on vial contents (and make a cell block).
Role of HPV testing in NZ
The NZ Cervical Screening Programme is planned to become HPV first in July 2023. At moment hrHPV testing is performed on squamous lesions for:
1. Triage of ASCUS / LSIL in people over age of 30
- if no abnormal smear in past 5 years and over 30
- hrHPV subtype present - go to colp
- hrHPV subtype absent - repeat cytology in 12 months
2. Test of Cure after Treatment for HSIL
- paired testing with cyto and hrHPV on 2 occasions, 12 months apart
3. On Specialist request after discordant results
- usually requested at time of colposcopy due to discrepancies in histo, cyto and colposcopy findings
Bethesda System for Thyroid Cytology
Standardised tiered reporting system that ensures unambiguous communication to clinician re: the ROM and what next management steps should be.
Always need to interpret cytology findings in clinical and radiologic context.
I - Non - Diagnostic
- virtually acellular specimens
II- Benign
- benign follicular nodule, lymphocytic thyroiditis, subacute thyroiditis
III - Atypia of Uncertain Significant (or FLUS)
- lots of criteria but not to be used as a wastebasket…
IV - Follicular Neoplasm (Suspicious for Follicular Neoplasm)
- specify if oncocytic type
V - Suspicious for Malignancy
- specify if PTC, medullary, lymphoma, metastasis
VI - Malignant
- specify if PTC, PDTC, anaplastic thyroid carcinoma, medullary, metastatic, NHL
Breast FNA Diagnostic Categories
C1 Inadequate
C2 Benign
C3 Atypia uncertain significance
C4 Suspicious for malignancy
C5 Malignant
Milan System for Salivary Gland Cytopathology
Evidence based, standardised, tiered reporting system for salivary gland cytology.
Allows clear communication between clinicians with a focus on risk stratification.
Six diagnostic categories, one non-diagnostic category. Primary salivary gland tumours plus others.
I - Non Diagnostic
- insufficient material for diagnosis, having processed and examined everything
- exceptions: matrix material and mucinous cyst content
II - Non Neoplastic
- Inflammatory, metaplastic and reactive changes e.g. chronic sialadenitis, reactive lymph node, granulomas
III - Atypia of Uncertain Significance
- Neoplasm cannot be excluded, most will represent reactive atypia or undersampled neoplasm
IV - Neoplasm
IVA - Benign neoplasm: eg. PA, WArthins, lipoma
IVB - SUMP: where a malignant neoplasm cannot be excluded. Most will be cellular benign neoplasms, neoplasms with atypical features and low grade carcinomas
V - Suspicious for Malignancy
- suggestive but non-diagnostic of malignancy. Should state what type of tumour is suspected or provide a list of differential diagnoses, e.g basaloid neoplasms, oncocytic neoplasms etc.
VI - Malignant
- try to classify / subclassify into type and grade of carcinoma
- includes other neoplasms such as lymphoma, metastases, sarcomas
