Introduction
Cytological examination of effusions is one of the commonly performed investigations. It has been universally recognised as the most important diagnostic tool in the recognition of malignant tumours in effusions. The cytodiagnosis by CS method have low sensitivity due to overcrowding of cells, cell loss and different laboratory processing methods. Therefore CB technique is usually recommended along with CS method for diagnosis of neoplastic effusions.1
The CB technique is one of the oldest methods for the evaluation of effusions. The CB preparation concentrates the cells in a limited field without loss of cellular material and tissue architecture.The advantage of CB is the availability of multiple sections of the same material. From CB, we can go for further ancillary techniques to diagnose malignancy causing effusions. Cell Block is of particular value in effusion samples subjected to immunohistochemical staining (IHC) to elucidate the occult primary site of tumour. Besides primary diagnosis, IHC test on cell block is also useful for prognostication. 2 The aim of this study is to evaluate the cytomorphological features of ascitic and pleural fluids by the CS and the CB method, to compare them and also to assess the utility of their combined approach in the diagnosis of malignancy. Very few literature available about this topic which prompt us to do the study.
Materials and Methods
The present study was conducted on 110 patients, after taking written informed consent, who underwent pleural and peritoneal tapping for the cytological diagnosis of effusions by conventional and cell block methods. It is a hospital based cross sectional study. A total of 110 specimens (64 ascitic and 46 pleural fluids) were received in the Cytology section, Department of Pathology, Gauhati Medical College and Hospital. Both sexes and all age groups, from May 2020 to April 2021 were included in the study. Clotted fluid samples, time between collection and processing more than one hour were excluded from our study.
Each fresh fluid specimen was divided into two equal parts. One part was subjected to the CS cytology technique and the other part was subjected to CB technique. In CS technique, the sample was centrifuged at 2500 rpm for 15 minutes. Two thin smears were prepared from the sediment. One was stained with the May- Grunwald-Giemsa (MGG) stain and other was stained with Papanicolaou (PAP) stain. In CB method, the fluid sample after centrifugation, the supernatant was poured off and one drop of pooled plasma and two drops of thromboplastin (1:2 ratio) were added to the sediment and centrifuged again at 2500 rpm for 3 minutes for proper aggregation of the sediments. Then 10% formalin is added slowly by the side of the tube and allowed to be fixed for 8 hours. The clot is then wrapped in filter paper and processed in histokinette as part of routine paraffin embedded section preparation. Paraffin embedded cell block sections were stained by Hematoxylin and Eosin stain. Sections were mounted by DPX mountant and examined under microscope.3
The CS and CB sections were examined separately for cellularity, architectural patterns and morphology (cytoplasmic and nuclear details) to come at a cytological diagnosis for each case and the findings of each case were compared. The smears were categorised as Inadequate, Benign, Atypical, Suspicious and Malignant pleural and peritoneal effusion. Yield for malignancy were identified by both the CS and the CB method. Data was entered into Microsoft excel 2007 sheet and analysed. Chi- square test and p-value (<0.05) were calculated. Assessment and comparison between both the CS and CB methods were carried out.
Result and Observations
Out of total 110 specimens studied, 46(41.82%) were pleural fluid, 64(58.18%) were ascitic fluid.
Age distribution
Table 3
Age distributions
|
Age group (in years) |
Patient no. |
|
13-22 |
2 (2%) |
|
23-32 |
11 (10%) |
|
33-42 |
12 (11%) |
|
43-52 |
28 (25%) |
|
53-62 |
19 (17%) |
|
63-72 |
13 (12%) |
|
73-82 |
15(14%) |
|
83-92 |
10(9%) |
Most commonly affected age group is 43-52 year group and least affected group were 13-22 year group. In Ascitic fluids, the number of transudates are 34 and exudates are 30. In Pleural fluids, the number of transudates are 25 and exudates are 21.
Table 4
Distribution of fluids according to their nature
|
Fluids |
Transudate |
Exudate |
|
Ascitic |
34 |
30 |
|
Pleural |
25 |
21 |
Table 5
Comparison of various findings in CS and CB method
|
No |
Diagnostic Category |
CS Method |
CB Method |
|
1 |
Malignancy |
14 |
29 |
|
2 |
Suspicious for malignancy |
16 |
1 |
|
3 |
Benign |
75 |
77 |
|
4 |
Atypical |
3 |
2 |
|
5 |
Inadequate/Non Diagnostic |
2 |
1 |
|
|
Total |
110 |
110 |
Table 6
Various type of malignancy in pleural andascitic fluid in CB method
|
Malignancy type |
Pleural fluid |
Ascitic fluid |
|
Adenocarcinoma |
9 |
10 |
|
Squamous |
2 |
5 |
|
Lymphoma |
1 |
0 |
|
Leukemia |
1 |
0 |
|
Urothelial cell malignancy |
0 |
1 |
Table 7
Type of different benign causes of effusions in CB method
|
Category of non-neoplastic effusion |
Total |
Percentage |
|
Reactive mesothelial cells |
37 |
48.05 |
|
Granulomatous |
22 |
28.58 |
|
Infective nature |
18 |
23.37 |
|
Total |
77 |
100 |
Amongst the total number of specimens studied, males predominantly had pleural effusion and females had ascitic effusion. Most common primary site in malignant ascitic effusion was found to be ovary, whereas the most common primary site in malignant pleural effusion was found to be lung.
By the CB method, an additional yield of fifteen (15) more malignant effusions ie., 13.64% more cases were detected as malignant [or we can say discrepancy rate is 13.64% between CS and CB method]. These samples were reported as either suspicious for malignancy or benign samples.
Out of 29 malignant effusions (pleural and ascitic effusion), 16 were female patients and 13 were male patients. Male is to female ratio was 1: 1.23
Figure 1
a: Microphotograph of Metastatic adenocarcinoma from ovary. Coventional smear (10x40), MGG stain; b,c: Cell block preparation of metastatic adenocarcinoma from ovary (10x40), H&E stain.
Figure 2
a: Microphotograph of Metastatic adenocarcinoma from lung, Conventional smear (10x40), MGG stain; b: Metastatic adenocarcinoma from lung,Conventional smear (10x40), PAP stain; c: Cell block preparation of metastatic adenocarcinoma from lung (10x40), H&E stain.
Figure 3
a: Microphotograph of T-cell ALL of pleural fluid, Conventional smear preparation (10x40), MGG stain; b: Cell block preparation of T-cell all of pleural fluid (10x40), H&E stain
Discussion
The present study “Cytomorphological evaluation of ascitic and pleural fluid with special reference to cell block method” was carried out in the Department of Pathology of Gauhati Medical College and Hospital, Guwahati for a period of one year from May 2020 to April 2021. A total of 110 effusion samples from Ascitic and Pleural cavities were collected.
The cytological study of serous effusions is one of the most definitive diagnostic tool for diagnosis of malignancy. It also helps in staging and prognosis of various malignancies.
Occurrence of malignant ascitic and pleural effusions is one of the most important features of various malignancies mainly ovarian and lung malignancies in this study.
Age group distribution
Age of patients in our study ranged from 13-92 years, maximum samples were in the age group of 43-52 years. Our study was similar to Priyanka R et al,4 where the most commonly affected age group was 41-50 years.
Table 8
Showing comparison of our study with other studies carried out by different study groups on distribution of age
|
Priyanka R et al4 |
41-50 years |
|
Present study |
43-52 |
Sample size distribution
The present study was done in Gauhati Medical College and Hospital and includes 110 effusion samples from ascitic and pleural cavities. Our study was similar to Santwani P.M et al 5 and Khan et al 6 where the sample sizes were 150 and 75 respectively.
Gender distribution
In our study, we found out that 40% cases were males and 60% were females indicating a higher prevalence of effusions in females. Our study was similar to Sumedha D et al 2 where prevelance of effusions was also more in females.Table 10
Table 10
Showing comparison of our study with other studies carried out by different study groups on distribution of gender
|
|
Male |
Female |
|
Sumedha D et al2 |
23 (54%) |
27 (46%) |
|
Present study |
44(40%) |
66(60%) |
Table 11
Comparison of increase in yield of malignancy by CB method of our study with other studies done by different study groups
|
|
Flint et al7 |
Bhanvadia Viral M |
Sumedha D et al2 |
Present study |
|
Increase In Malignancy Yield |
9% |
10% |
15.38% |
13.64% |
Table 12
Comparison of cytodiagnosis of effusions of our study with other studies (CS only)
|
S.No |
Study |
No of cases |
Specimen |
Malignant |
Suspicious |
Benign |
Atypical |
Inadequate |
|
1 |
Dekker and Bupp, 8 |
173 |
Pleural, Ascitic and pericardial effusion |
28 |
8 |
128 |
9 |
0 |
|
2 |
Thapar M et al. |
190 |
Pleural, Ascitic and pericardial effusion |
70 |
0 |
120 |
0 |
0 |
|
3 |
Present study |
110 |
Pleural and ascitic fluid |
14 |
16 |
75 |
3 |
2 |
Table 13
Comparison of cytodiagnosis of effusions of our study with other studies (CB only)
|
S.No. |
Study |
No of cases |
Specimen |
Malignant |
Suspicious |
Benign |
Atypical |
Inadequate |
|
1 |
Sumedha D et al, 2 |
50 |
Pleural and Ascitic effusion |
24 |
6 |
20 |
0 |
0 |
|
2 |
Kulkarni MB et al3 |
38 |
Pleural, Ascitic and Pericardial effusion |
23 |
0 |
15 |
0 |
0 |
|
3 |
Present study |
110 |
Pleural and ascitic fluid |
29 |
1 |
77 |
2 |
1 |
Diagnostic yield comparison
In our study, the increase in yield of malignancy was 13.64%, which was similar to the studies done by Flint et al, 7 Santwani P.M et al 5 and Sumedha D et al, 2 where the increase in yield of malignancies were 9%, 10% and 15.38% respectively.Table 11
In our study by CS method, 14 cases were found to be malignant, 16 were suspicious, 75 were benign, 3 were atypical and 2 were found to be inadequate. Our study was similar to Dekker and Bupp, 8 where 28 cases were found to be malignant, 8 suspicious, 128 benign and 9 were atypical cases. Our study was also similar to Thapar M et al 9 where 70 cases were found to be malignant and 120 benign cases. Table 12
In our study, 29 cases were found to be malignant, 1 was suspicious, 77 were benign, 2 were atypical and 1 case was found to be inadequate. Our study was similar to Sumedha D et al,2 where 24 cases were found to be malignant, 6 were suspicious and 20 were benign. Our study was also similar to Kulkarni MB et al,3 where 23 cases were found to be malignant and 15 cases were found to be benign.Table 13
Conclusion
The present study shows that it is advisable to routinely make cell blocks in every atypical, suspicious and malignant cases found by conventional smear method. Cell block method is an easily available, better diagnostic tool for diagnosis of malignant effusions. Ancillary techniques can also be used in cell block method for diagnosing specific type of malignancy and in evaluation of primary site.
