| Abstract|| |
Introduction: Transthoracic guided fine needle aspiration cytology (FNAC) of clinically suspected lung tumors is an increasingly common procedure in diagnosis. Cytospin Smear and Cellblock preparations of available material are helpful in subtyping and confirming the diagnosis, and they can also be used for further studies, i.e., special stain and immunohistochemistry, etc.
Aims and Objectives: This research was undertaken to study the technique of guided transthoracic lung FNAC of clinically suspected lung tumors and the establish role of FNAC smears, cytospin smears, and cellblocks in the detection and typing of neoplastic lung lesions and correlation.
Materials and Methods: Guided FNAC was taken from 100 cases of clinically suspected lung tumor and FNAC smears, cytospin smears, and cellblocks of aspirated material were studied over a period of 2 years from September 2011 to September 2013.
Results: The material adequacies were 80% in FNAC smears, 83% in cytospin smears, and 89% in cellblocks. Additional information supported by cytospin smear and cellblock was 3% and 9%, respectively. Architectural preservation was better in FNAC smears (85%) and cellblocks (73.03%) than that in cytospin smears (31.33%). Morphological preservation was better in FNAC smears (90%) and cellblocks (75.28%) than that in cytospin smears (14.46%). Diagnostic accuracy was increased in the cellblocks and cytospin smears.
Conclusion: Cytospin smear was helpful when low cellular material was obtained, and the concomitant examination of cellblocks not only confirmed the diagnosis of malignancy but also helped in classifying the obtained material and allowed further study on the same.
Keywords: Cellblock; cellblocks; cytospin; cytospin smear; lung tumors; transthoracic fine-needle aspiration cytology (FNAC); transthoracic lung FNAC
|How to cite this article:|
Kshatriya AS, Santwani PM. Comparison of FNAC smears, cytospin smears, and cellblocks of transthoracic guided FNAC of suspected lung tumor: A study of 100 cases. J Cytol 2016;33:141-4
|How to cite this URL:|
Kshatriya AS, Santwani PM. Comparison of FNAC smears, cytospin smears, and cellblocks of transthoracic guided FNAC of suspected lung tumor: A study of 100 cases. J Cytol [serial online] 2016 [cited 2020 Sep 30];33:141-4. Available from: http://www.jcytol.org/text.asp?2016/33/3/141/188051
| Introduction|| |
Transthoracic fine-needle aspiration cytology (FNAC) is a well-known, safe, and convenient diagnostic procedure that helps in the early diagnosis of clinically suspected lung tumors. It is further improved by radiological techniques, such as ultrasonography (USG) and computed tomography (CT) scan, which permitted a better guidance and improved the modalities to limit complications.  From aspirated material, FNAC smear, cytospin smear, and cellblocks can be prepared. In the cellblocks, cellularity is increased, the morphological details are better observed, and special histochemical stainings and immune histochemical studies can be done.  The cytospin smear method provides cellularity even in cases where FNAC smear shows unsatisfactory cellularity,  which increases the diagnostic potential. The cytospin smear can be further utilized for special stains and immunohistochemistry, etc. FNAC smears, cytospin smears, and cellblocks have been evaluated to established the correlation in this study.
| Materials and Methods|| |
This prospective study was carried out following the permission of the institutional ethics committee and proper patient consent in the Department of Pathology in collaboration with the Department of TB and Chest Respiratory Medicine and Department of Radio-diagnosis over a period of 24 months (September 2011 to September 2013). A total of 100 patients with clinically suspected lung tumor were included in the study.
A thorough work-up of the patients were carried out including detailed history, previous records, clinical examination, routine screening with hemogram, urine analysis, and microbiological and cytological examination of sputum, posteroanterior, and lateral view radiograph of thorax and USG of thorax and abdomen. Transthoracic FNAC was done under USG and CT scan guidance in the presence of qualified radiologist with 22- or 23-gauge of simple injection needle or spinal needle depending upon site and depth of lesion, attached with a 20 mL syringe. Material for the cellblock and cytospin smear was taken after making routine FNAC smear, which was given priority. Four FNAC smears were prepared and fixed immediately in 95% ethanol for routine staining with hematoxylin and eosin (H&E) stain and Papanicolaou (PAP) stain and remaining material in the hub of needle was washed in 10% formal saline for cytospin smear and cellblock preparation. Cytospin smears were prepared with cytocentrifuge technique and cellblocks were prepared with plasma thrombin method and commercially available HISTOGEL method. Cytology smears, cytospin smears, and cellblocks were stained with H&E and PAP stains and studied for correlation.
| Results|| |
The study comprised of 100 patients with clinically suspected lung tumor, and they were subjected to USG or CT scan guided transthoracic FNAC of the lesion.
Out of 100 patients, 94 patients (94%) were males and 6 patients (6%) were females with male:female ratio of 15.6:1. The majority of patients were presented in the 6th decade of life (40%) followed by 5th decade (29%). Right sided lesions (68%) were more than the left-sided lesions (32%), and the upper (42%) and middle zones (42%) were more affected on both sides than the lower zone (16%).
Out of total 100 cases, definitive diagnosis were possible with FNAC smears in 80% cases, with cytospin smears in 83% cases, and with cellblock in 89% cases. Diagnostic accuracy was increased 10% by combining FNAC smears, cytospin smears, and cellblocks. In 10% cases, inadequate material was found in all three preparations. When FNAC smears had no diagnostic material, additional information supported by cytospin smears and cellblocks was 3% and 9%, respectively [Table 1]. Cellularity was high in cytospin smears and direct smears than that of in cellblocks [Table 2].
|Table 2: Comparison of diagnostic material by various methods (N = 100) |
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Architecture preservation was comparable in FNAC smears (85%) and cellblocks (73.03%), while in cytospin smears architectural preservation was poor (31.33%) and morphological preservation was better in FNAC smears (90%) as compared to cellblocks (75.28%) and cytospin smears (14.46%) [Figure 1] and [Figure 2].
|Figure 1: FNAC smears: (a) adenocarcinoma (H&E stain, ×400), (b) small cell carcinoma (H&E stain, ×400) cytospin smears: (c) adenocarcinoma (H&E stain, ×400), (d) small cell carcinoma (H&E stain, ×400)|
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|Figure 2: Cellblocks: (a) squamous cell carcinoma (H&E stain, ×400), (b) adenocarcinoma (H&E stain, ×400), (c) small cell carcinoma (H&E stain, ×400), (d) metastatic renal cell carcinoma (H&E stain, ×400)|
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Among methods of cellblock preparation, diagnostic material was higher in commercially available HISTOGEL method (91.93%) than plasma thrombin method (81.58%).
Final cytological diagnoses were possible in a total 90 cases, among which 80 were malignant, 2 were benign/inflammatory, and 8 cases were diagnosed as suggestive of malignancy. In few cases, the discordance in diagnosis was found in FNAC smears, cytospin smears, and cellblocks. Confirmed diagnosis of malignancy and subclassification of malignancy on FNAC smears was made in 73 cases, and on cytospin smears in 67 cases, and on cellblocks in 80 cases.
Discordance was found in three cases in diagnosis of malignant lesions by FNAC smears and cellblocks. One case that was diagnosed as nonsmall cell carcinoma on FNAC smear, the cellblock diagnosis was adenosquamous carcinoma. Other case was undifferentiated squamous cell carcinoma (SCC) on FNAC smear and poorly differentiated adenocarcinoma on cellblock, while another case was diagnosed SCC on FNAC smear and small cell carcinoma of intermediate cell variant on cellblock.
| Discussion|| |
The study was undertaken to look into the accuracy of FNAC smears, cytospin smears, and cellblocks alone and to study the combined effectiveness in diagnosing the malignant lesions of lung.
Majority of the patients were presented in the 6th decade of life (40%) followed by those who presented in the 5th decade of life (29%) in this study, which is in accordance with other studies. ,, Right-sided lesions (68) were common than left-sided lesions (32) which is accordance with the text and various other studies. ,
On comparison of diagnostic cellularity grading system,  in FNAC smears and cellblocks, no cellularity is found in 20% and 11% cases, respectively, which is more as compared to another study (0% and 8.5%),  and low score cellularity is found in 8% and 19% cases, respectively, which is less as compared to another study (11% and 40%).  While moderate-to-high score cellularity is found in 72% and 70% cases, respectively, which is comparable with another study (96% and 57%).  While in cytospin smears, 17% cases with no cellularity, 7% cases with low score cellularity, and 76% cases with moderate-to-high score cellularity were observed.
We found that diagnostic material was superior in cellblocks (89%) than that in FNAC smear (80%) while Khan et al.  (100%) and Nathan et al.  (84.8%) found higher diagnostic material in FNAC smear than in cellblocks as was found by Khan et al.  (91.5%) and Nathan et al.  (73.3%). We found that, diagnostic material in cytospin (83%) was better and useful, when the FNAC did not show satisfactory material, which was in accordance with other study.  Thus, cytospin smears may be useful sometime when there is low or no diagnostic material in FNAC smears.
In this study, cytospin smears and cellblocks increase the accuracy of diagnosis by 3% and 9% cases, respectively, which was in accordance with other study (2% and 10%).  Overall diagnostic accuracy increased in 10% of cases. It is true that the combination of techniques helps to increase the diagnostic yield and positivity to reach the diagnosis.
The architecture preservation  means the presence or absence of tissue architecture as evidence by cellular relationship with each other, e.g., a honeycomb arrangement in adenocarcinoma or molding in small cell carcinomas. This shows that the architecture preservation in FNAC smears is 85%, which is low as compared with other study (100%),  and the architecture preservation in cellblocks is 73.03%, which is high as compared to other study (47%),  but in cytospin smear preparations the architectural preservation is only 31.33%.
The morphological preservation  means the presence or absence of crisp, clear nuclear chromatin, nuclear margin, cytoplasm contents, and cytoplasmic membrane. This study shows that morphological preservation is better in FNAC smears (90%) than that in cellblocks (75.28%), which is comparable with other study (100% and 87.23%),  while in cytospin smears, the morphology is well preserved only in 14.46% cases. This may be because of the degeneration of cells in cytospin smears and cellblocks due to the delay in immersing sample into fixative and the variation in FNA technique as repeated needle pass may traumatize cells. The morphological preservation can be improved by modifying techniques and decreasing the time lapse between aspiration, fixation, and preparation of cellblocks and cytospin smears.
Diagnostic yield observed by plasma thrombin method was 81.58%, which was comparable with other study (78.60%).  By using HISTOGEL for cellblock preparation, it was possible to capture small groups of cells and give high diagnostic yield (93.55%) as compared to plasma thrombin method. It prevents histotechnologist from cutting too deeply into the block and risk of missing the area with cells of interest.
| Conclusion|| |
FNAC smears are better for evaluations but have little disadvantages in case of little or inadequate material and the search of material is very time-consuming and require patience in that case. Cytospin smears are useful in cases where there is no diagnostic material in FNAC smears, only 6 × 6 mm area having cellularity, so it is less time-consuming and extra smears can be used for special stains but cell morphology is distorted in cytospin smears.
Cellblock method allows the recovery and processing of minute amounts of cellular material and facilitates the better classification of tumor when reviewed along with cytological smears and can be used for special staining and immunohistochemistry for further assessing the lesion. Cellblock supports in the final cytological diagnosis therefore it should be considered in all FNAC specimens whenever possible. Routine preparation of the cellblock improves the accuracy of the FNAC diagnosis but it cannot replace the direct FNAC smears.
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Conflicts of interest
There are no conflicts of interest.
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Dr. Ankur Singh Kshatriya
A-141, Meera Park, Narayan Nagar, Khodiya Nagar, Ahmedabad - 382 350, Gujarat
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2]
[Table 1], [Table 2]