Cytology - principles

Question 1

preserving liquid specimens

Answer 1

keep in fridge until processed

add preservative for urine (degenerates even in fridge) or longer storage

Question 2

processing fluid specimens - options

Answer 2

1. cytospin with air dry (Roanowsky stain) or ethanol fixation (Papanicolaou stain)
2. liquid based processing (ThinPrep and SurePath)
3. cell block (clot -> fix -> embed)

Question 3

fluid specimens - ancillary tests

Answer 3

immunocytochemistry: cell blocks preferred, but can stain direct (eg MPX for leukaemia)

flow cytometry

molecular genetics: can extract material from air dried, wet fixed and cell blocks

Question 4

advantages of FNA (6)

Answer 4

relatively painless

fast diagnosis

inexpensive

info for pretreatment planning

low technical skill

complications rare

Question 5

limitations of FNA

Answer 5

may be inadequate/nonrepresentative

specific diagnostic criteria not possible (eg capsular invasion in follicular thyroid lesion)

Question 6

FNA biopsy procedure

Answer 6

review history

identification patient and slides

informed consent (indications, procedure, complications)

clean area, 3 passes, pressure at site

direct smear (wet and/or dry fix) plus needle rinse to RPMI

additional material for micro/flow if needed

Question 7

cytology of different staining methods

Answer 7

cell block: as per histology (‘hard-boiled egg’)

wet fixed: similar nuclear size, cytoplasm slightly larger (‘poached egg’)

air dried: larger nucleus and cytoplasm (‘fried egg’)

Question 8

general categories for diagnosis (some changes in diiferent systems)

Answer 8

1. insufficient
2. negative for malignancy
3. atypical cytology
4. suspicious for malignancy
5. positive for malignancy

Question 9

sources of error in FNA biopsy

Answer 9

inadequate sampling: localisation, technique, fibrosis, dilution (eg blood)

inadequate processing: blood clot, drying artefact, poor smear

not identifying abnormal cells

not interpreting abnormal cells correctly

Question 10

Bethesda categories for thyroid cyto (and treatment)

Answer 10

I. nondiagnostic - repeat FNA

II. benign - follow up

III. atypia of undetermined significance - repeat FNA

IV. follicular neoplasm (specify if Hurthle) - lobectomy

V. suspicious for malignancy - lobectomy

VI. malignant - thyroidectomy

Question 11

Bethesda categories for cervical cyto

Answer 11

adequacy (need 5000 cells or 4 per HPF)

negative for intrepithelial lesion - nonneoplastic/reactive, organisms (trich, candida, HSV, actinomyces, bact vaginosis, CMV), other (endom cell >45yo)

epithelial cell abnormality

Question 12

Bethesda cervical categories - epithelial cell abnormalities

Answer 12

atypical squamous cells (ASC-US or ASC-H)

LSIL

HSIL

SCC

atypical glandular cells (NOS or suspicious for AIS/cancer)

AIS

Question 13

Paris urology cytology categories

Answer 13

negative for HGUC

atypical urothelial cells

suspicious for HGUC

HGUC

low grade urothelial neoplasia

other malignancies (primary/secondary)

Question 14

Papanicolaou biliary cytology

Answer 14

non-diagnosistic

negative for malignancy

atypical

neoplastic benign or other

suspicious for malignancy

malignant