This study compares the efficacy of liquid-based cytology (LBC) to conventional smear methods for fine needle aspiration cytology samples. The study analyzed 110 cases of various lesions collected over 2 years. Results showed that LBC produced more clear backgrounds and better preserved and dispersed cells compared to conventional smears. LBC allowed for improved diagnosis of lesions like ductal carcinoma, lymph node metastases, and bone lesions. However, LBC required more processing and had some artifacts that could complicate interpretation. Overall, LBC improved sample quality and reduced inadequate sampling compared to conventional smears.

1. Journal of Cytology / January 2015 / Volume 32 / Issue 1
Tripathy, et al
Department of pathology, Shrirama Chandra Bhanja Medical College,
Cuttack, Odisha, India

2.  What does 'Liquid Based Cytology‘ mean?
 It means cytology (study of cells )through a liquid medium.
 Liquid-based cytology (LBC) as a technique was introduced
and tried on Pap smears.
 It received the Food and Drug Association (FDA) approval in
1996.[1]
 Thereafter, this technique was performed for non-
gynecological cytology, including conventional fine needle
aspiration cytology (FNAC), guided FNAC and fluid cytology.

3.  Cells are collected from cervix or any other site and are placed
directly into liquid preservative, rather than transferred to
slide.
 Sample is processed and resultant thin smear is easy to screen.
 The thin-prep (TP) smears were consistently devoid of
obscuring elements and the cells were adequately preserved
and evenly dispersed.

4. FDA approved
 Thin Prep:
◦ Filtration and collection of vacuum packed cells on a membrane &
transferring to glass slide
 Sure Path:
◦ Centrifugation & sedimentation through a density gradient
Not FDA approved
 Cytoscreen
 Turbitac
 Cellslide
 Papspin
◦ Centrifugation and sedimentation by manual techniques.

5. Thin prep Sure Path

6. 1. Dispersion 2. Cell Collection 3. Cell Transfer

7. The prepared slide with the new thin prep

9.  Relatively inexpensive method
 Equipments required- vortexer and
Laboratory centrifuge

12.  Continuing improvement to the Cervical screening Programme
 Limitations of conventional cytology because there is
suboptimal preservation of cells and cellular obscuring by
unwanted material, leading to a high proportion of cases
reported as inadequate or unsatisfactory for assessment
 Modernisation of the technique
 Extra tests – HPV, chlamydia, Neiseria, Gonorrhoea.

13.  Simplifies the collection process for the smear taken
 Reduced inadequate rate
 Cells better preserved and not obscured by blood, mucus, or
inflammatory cells
 Infectious organisms retained and better preserved
 Quicker to screen and report
 Multiple slides can be produced allowing further testing
 Residual material in the vial can be made available for further
tests eg; HPV tests
 Facilitates computer assisted screening which can be available
in future(automated cytology)

14.  More costly than conventional pap smears
 Preparation is more labor intensive than conventional
 Loss of background material
 Some differences in architecture and morphology
 Requires training for both the screeners and the smear takers

15. Conventional Pap Smear
-Majority of cells not captured
-Non-representative transfer of cells
-Clumping and overlapping of cells
-Obscuring material
LBC
-Virtually all cells of sample are
collected
-Randomized, representative
transfer of cells
-Even distribution of cells
-Minimizes obscuring material

17.  Although studies on LBC are documented for breast,
non-gynecologicalspecimen, thyroid, salivary gland
and soft tissues, the authors supplemented bone
lesions to all the above in their study.

18.  This study was conducted in a 2000-bedded hospital.
 The aim of study was to determine the efficacy of LBC
technology over conventional smear methods in FNAC
samples.
 The study was performed on patients attending the Cytology
Outpatient Department (OPD) of the hospital over a period of
2 years.
 Dry tap samples were not included in the study.
 Samples lost during processing were also rejected.
 A total of 110 cases were studied.

19.  For LBC, samples were processed using the LiquiprepTM
processing kit.
 Processing was performed manually in three steps, i.e.
collection, concentration and cellular encapsulation.
 The LB cytology processing kit contains a preservative
solution, a cleaning solution and a cellular base solution.
 Using the LBC processing kit, the first step is collection of
samples.
 Here, the samples were pushed into a preservative solution,
approximately three-times the volume of the sample, and left
as such for at least 1 hour.

20.  This is followed by the next step, i.e. concentration, where the
preserved sample is centrifuged at 3000 rpm for 30 min.
 For cystic fluids, the supernatant fluid is discarded and, after
adding the cleaning solution, it is again centrifuged for 15 min
to increase its concentration.
 A pellet is produced, the supernatant fluid is discarded and a
base solution of about 50 microlitre is added to the pellet to
make a thin, homogenous suspension

21.  Suspension was placed on an ethanol-cleaned glass slide
 Two circular smears of 1 cm diameter were made.
 The second option, which uses a cellular base solution, was
used in certain cases, particularly if the sample contains
necrotic substance or mucin.
 About 4 mL of cleansing solution was used in selected cases,
along with the preservative solution, and the processing was
performed in a similar fashion.
 This study used both the options.

22.  For each FNAC, two passes were performed, the first pass was
for CP and the second pass yielded material for the TP
preparation, which was processed by the TP kit marketed by
Cytcec Corporation.
 Different stains were used for staining the CP and LP smears,
like HE, Pap and Diff Quik.
 The representative CS and LB preparations were compared by
a semiquantitative scoring system using several criteria [Table
1].

24.  The concentration method used in the procedure was useful in
the diagnosis of cystic lesions like aneurysmal bone cysts,
Warthin’s tumor of salivary glands and metastatic carcinoma
 Statistical analysis was performed using the Wilcoxon signed
rank test on the SPSS program (Chicago, IL, USA).
 Every cytological diagnosis was recorded and tabulated and
compiled to yield the P-value.
 P-value is the probability of occurrence of the research
finding.
 P < 0.005 is significant.
 The lesser the P-value, the more accurate is the result.

25.  A total of 110 cases were studied, which were distributed
among
◦ 30 cases of breast (10 fibroadenoma, 8 mastitis and 12 ductal
carcinoma),
◦ 40 cases of lymph node (20 reactive hyperplasia, 12 granulomatous
lymphadenitis, 3 lymphoma and 5 metastatic carcinoma),
◦ 10 cases of salivary gland ( 2 sialadenitis, 5 mixed tumor, 1 Warthin’s
tumor and 2 mucoepidermoid carcinoma),
◦ 18 cases of thyroid (10 colloid goiter, 4 thyroiditis and 4 carcinoma
cases)
◦ 12 cases of soft tissue and bone lesions (5 benign and 7 malignant).

26.  Pitfalls noticed as cytomorphologic alterations in LBCs are
 small-sized cell clusters, with more single cells than sheets.
◦ The cells are generally smaller, occasionally show spindling
◦ chromatin detail is attenuated,
◦ nucleoli are more prominent,
◦ intranuclear inclusion is difficult to visualize,
◦ decrease of extracellular particles is seen,
◦ there is a decrease in the number of small mononuclear
cells/red blood cells/myoepithelial cells and
◦ the background matrix is altered.

27.  Comparison between cytologicalfeatures in LBC and CS was
carried out using the Wilcoxon signed rank test separately for
each organ.
 In this study, in two cases of pleomorphic adenoma, one case
of Warthin’s tumor and two cases of colloid goiter, a support
of CS was needed due to pitfalls in LBC described above.
 All the bony lesions were perfectly diagnosed in LBC.

28.  For breast cases, fibroadenoma, mastitis and ductal carcinoma
were better diagnosed on LBC preparations due to clarity of
the nuclear features [Figure 1].
 In fibroadenoma breasts, although stromal fragments were
lost, LBC proved to be useful in the diagnosis based on
visualization of ductal aggregates and bipolar cells.
 For duct carcinomas, the same criteria were useful
 Comparison data for lymph nodes suggested that the RS cells
were more easily diagnosed on LBC smears due to
monolayering.
 Immature lymphoid cells and foreign cells were also better
visualized because of similar reasons.

30.  In case of salivary gland lesions, the mixed salivary tumor was
better visualized in the conventional smear because of
preservation of the stromal component.
 Cystic neoplasms of the salivary glands like Warthin’s tumor,
mucoepidermoid and adenoid cystic carcinoma were better
appreciated in LBC smears because of concentration.
 In sialoadenitis, the LBC preparations were superior to the CP
smears.

31.  In the thyroid gland, LBCs were not very useful in goiter and
infectious lesions, but they proved very useful in neoplastic
lesions especially anaplastic and medullary carcinoma.
 In lytic bone lesions like aneurismal bone cyst (ABC), giant
cell tumor (GCT) and metastasis, better results were obtained
by LBC preparations because of background clearing and
concentration phenomenon
 In soft tissue lesions, LBC showed good results because of
lack of background material.

33.  Because of the pitfalls of LBC, as described above, in some
selected cases of granulomatous lymphadenitis (lacking
epitheloid cells), mucinous tumors (lack of mucin), colloid
goiter (thin colloid fragmented) and pleomorphic adenomas of
the salivary gland (myxoid background poor and present in
droplets), a support on CS may prove useful.
 As observed by the authors, LBC of bony lesions do not
require support of CS.

34.  TP preparations are superior to CPs with regard to clear
background, monolayer cell preparation and cell preservation.
 It is easier and less time consuming to screen and interpret TP
preparations because the cells are limited to smaller areas on
clear backgrounds, with excellent cellular preservation.

35.  However, TP preparations are more expensive than CP and
require some experience for interpretation.
 Familiarity with artifacts is essential to avoid misdiagnosis.
 LBC is strongly advocated in the best interest of public health,
by improving the quality of the sample and reducing the
likelihood of false negative cytology results.