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ORIGINAL ARTICLE  
Year : 2013  |  Volume : 56  |  Issue : 2  |  Page : 84-88
Cytohistological correlation in diagnosis of lung tumors by using fiberoptic bronchoscopy: Study of 200 cases


1 Department of Pathology, I.G.M.C., Shimla, Himachal Pradesh, India
2 Department of Pulmonary Medicine, I.G.M.C., Shimla, Himachal Pradesh, India

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Date of Web Publication23-Sep-2013
 

   Abstract 

Background: Examination of specimens obtained through flexible fiberoptic bronchoscope is an important and often the initial diagnostic technique performed in patients with suspected malignant lung lesion. Aims: To evaluate the correlation of cytological findings of bronchial washings, bronchial brushing and imprint smear of bronchial biopsy in the diagnosis of lung tumors, with histopathology of bronchial biopsy taking the latter as the confirmatory diagnostic test. Materials and Methods: A total of 200 patients with lung mass were included in the study. Bronchial brushings were obtained from all 200 cases. In the first 100 cases, pre-biopsy bronchial washing (washing collected before the brushing and biopsy procedure) while post-biopsy washing (washing at the end of the procedure) was procured in all 200 cases. Imprint smears of bronchial biopsy were prepared in 150 cases. Results: Sensitivity and specificity of brushing was 76.58% and 77.78% respectively and that of imprint smear was 81.35% and 78.12% respectively. Pre-biopsy and post-biopsy washing showed high specificity of 88.89%, but low sensitivity of 30.14 and 36.77% respectively. No significant difference was found in sensitivity between brushing and imprint smear (Chi-square; P = 0.4187); and between pre-biopsy and post-biopsy washing (Chi-square; P = 0.7982). However, there was a significant difference between sensitivity of brushing and washing (Chi-square; P = 0.0001). The sensitivity of combination of three cytological diagnostic techniques was 87.29%. Conclusion: Bronchial brushing and washing cytology in combination with imprint cytology aids in the diagnosis of lung tumors. Therefore, all these techniques may be used concurrently along with bronchial biopsy to diagnose lung tumors.

Keywords: Bronchial washing, brushing, fiberoptic bronchoscopy, imprint smear, lung cancer

How to cite this article:
Bodh A, Kaushal V, Kashyap S, Gulati A. Cytohistological correlation in diagnosis of lung tumors by using fiberoptic bronchoscopy: Study of 200 cases. Indian J Pathol Microbiol 2013;56:84-8

How to cite this URL:
Bodh A, Kaushal V, Kashyap S, Gulati A. Cytohistological correlation in diagnosis of lung tumors by using fiberoptic bronchoscopy: Study of 200 cases. Indian J Pathol Microbiol [serial online] 2013 [cited 2023 Mar 31];56:84-8. Available from: https://www.ijpmonline.org/text.asp?2013/56/2/84/118661



   Introduction Top


Lung cancer is the most frequently diagnosed cancer and also the leading cause of all cancer associated deaths in the world. [1] Previously bronchogenic carcinoma was considered to be infrequent in India, but in the recent past a trend of increase in its incidence has been noticed. [2] Lung cancer has been estimated to be the most frequent among all the new cases of cancers in male in this country. [3]

Bronchoscopy is perhaps the most invaluable tool for diagnosis of lung cancer. Various diagnostic techniques have been developed using flexible fiberoptic bronchoscopy. [4],[5] Cytological assessment of specimens of the respiratory tract is an important and often the initial diagnostic technique carried out in a patient with suspected malignant lung lesion. [6] The utilities of cytology is extensive and some time they help in planning the treatment without the requirement for an open biopsy. Both washing and brushing are very effective in the diagnosis and differential diagnosis of lung cancers. Brushings often offer excellent specimens and accurate information about the site of the lesion. [7] Imprint smears from bronchial biopsy has also been found to give a good diagnostic yield. [8] Among various bronchoscopic techniques, bronchial biopsy has the highest sensitivity for endobronchial malignant lesions. [9] Bronchial biopsy has also been used as the gold standard diagnostic test to assess the efficacy of other cytologic techniques. [10] Better diagnostic yield is often obtained when cytologic techniques are used together with bronchial biopsy. [11] In general the concordance between cytology and histopathology ranges from 70% to 90% and the bronchial biopsy is confirmatory for most of the cytological findings. [4]

In view of the importance of cytological methods in diagnosis of lung tumors and paucity of such studies from our state, the current study was planned with the objective of assessing the correlation of cytology of bronchial washings, bronchial brushing and imprint smear of bronchial biopsy in the diagnosing lung tumors, with histopathology of bronchial biopsy taking the latter as the confirmatory diagnostic test


   Materials and Methods Top


It was a prospective study conducted in the Department of Pathology of a teaching hospital. The samples for cytological and histological examination were collected from the indoor/outdoor patients in whom clinical findings, radiological examination and bronchoscopic examination suggested lung mass. A total of 200 cases were included in the study. The samples were obtained by flexible fiberoptic bronchoscopy done by the Pulmonologist. Bronchial brushings were obtained by the use of a stiff-bristle disposable brush. Brushing material was smeared directly on to at least three clean glass slides. The air dried smears were stained with Geimsa stain. In the first 100 cases, bronchial washing was obtained before the brushing and biopsy procedure (pre-biopsy washing). However, at the end of procedure bronchial washing (post-biopsy washing) was procured in all 200 cases. Samples were centrifuged and prepared into air dried smear. Staining was done with Giemsa stain. Imprint smears were prepared from the bronchial biopsy in 150 out of 200 cases. Imprint smears were prepared by placing forceps biopsy specimens of about 2 mm size on a glass slide and rolling over the surface. The smears were air dried and stained with Giemsa stain. Bronchial biopsies were fixed in 10% formalin and stained with H and E.


   Results Top


Majority cases (73.0%) were males with male female ratio of 3.35:1. The mean age of the sample was 62 years with a range of 25-89 years. Most of the patients were from a rural background (86.5%) and rural urban ratio was 6.41. Out of 200 cases subjected to bronchoscopy, lung cancer was confirmed in 155 (77.5%) cases by histopathology of bronchial biopsy as shown in [Table 1]. Among patients with lung cancer, 88.24% of male and 50% of females were active smokers at the time of assessment. Squamous cell carcinoma was found to be the commonest lung cancer (38.70%), followed by small cell carcinoma (27.10%) and adenocarcinoma (23.87%).
Table 1: Lung cancer distribution

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Morphological differentiation of lung cancer by different cytological techniques is shown in [Table 2]. All except one case of bronchial biopsy [Figure 1] could be differentiated in to a specific type of carcinoma. However, minority of washing [Figure 2] samples (6/22 in pre-biopsy and 15/57 in post-biopsy washing) which showed malignancy could be classified morphologically into a specific type of carcinoma. Bronchial brushing [Figure 3] and imprint smear cytology [Figure 4] were found to be better than washing cytology in morphological differentiation of lung tumor.
Table 2: Morphology of lung cancer by different techniques

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Figure 1: Bronchial biopsy of adenocarcinoma of lung (H and E, ×400)

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Figure 2: Bronchial washing shows squamous cell carcinoma (Giemsa stain, ×400)

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Figure 3: Bronchial brushing showing emperipolesis and tumor giant cell of large cell undifferentiated carcinoma (Giemsa stain, ×400)

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Figure 4: Imprint smear of bronchial biopsy showing small cell carcinoma (Giemsa stain, ×400)

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Comparison of various cytological techniques with bronchial biopsy is shown in [Table 3] and [Table 4]. Sensitivity and specificity of brushing was found to be 78.06% and 77.78% respectively and that of imprint smear was 81.35% and 78.12% respectively. Pre-biopsy and post-biopsy washing showed high specificity of 88.89%, but a very low sensitivity of 30.14 and 36.77% respectively.
Table 3: Results of cytological techniques compared to gold standard (bronchial biopsy)

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Table 4: Comparison of indices of cytological techniques

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There was no significant difference in sensitivity between brushing and imprint smear (Chi-square; P = 0.4187); and between pre-biopsy and post-biopsy washing (Chi-square; P = 0.7982).

However, there was statistically significant difference between sensitivity of brushing and washing (Chi-square; P = 0.0001). The sensitivity of combination of three diagnostic techniques brushing, imprint smear and washing is 87.29%.


   Discussion Top


The present study was conducted with the objectives of assessing the sensitivity and specificity of bronchoscopic cytological procedures; bronchial brushing, washing, imprint cytology by comparing with the histopathology of bronchial biopsy obtained from lung tumors.

In the present study, the bronchial brushing could detect malignancy in 121 out of 155 (78.06%) cases and we found a sensitivity of 78.06% and specificity of 77.78%. This finding of the present study is similar to the result that was observed by Mak et al.[12] and Chen et al. [13]

Imprint smear of bronchial biopsy had a sensitivity of 81.35% and in 69.07% (67/96) cases correct cell typing by imprint smear could be made. Previous studies have found almost similar results of positive rate of diagnostic yield from imprint smear of bronchial biopsy. [8],[14] However, as far as morphological typing is concerned a previous study had a higher rate of cell typing of different carcinomas among the positive imprint smear cases (86.1%) as compared to ours (69.07%). [8] Overall relatively fewer literatures are available that evaluated the imprint smear of the bronchial biopsy in the diagnosis.

Bronchial washing is often used along with bronchial brushing and biopsy to diagnose lung cancer. However, the optimal timing of bronchial washing with respect to biopsy and brushing (i.e., whether before or after biopsy and brushing) has been subject to debate. In order to assess the optimal sequence in which bronchial washing be performed, the washing was obtained in two ways in the present study: Pre-biopsy washing and post-biopsy washing. Sensitivity of pre-biopsy washing was found to be 30.14% and that of post-biopsy washing was 36.77% in patients of lung cancer confirmed by bronchial biopsy. Previous studies by Buccheri, et al., [15] Park et al. [16] and Karahalli et al. [17] had found almost comparable result of bronchial washing in lung cancer cases. However, in many other previous studies by Solomon et al., [18] van der Drift et al., [19] Fernαndez-Villar et al., [20] Khan and Rafi [21] the diagnostic yield of bronchial washing was at variance with that of our study. On comparing, no significant difference was found between sensitivity of pre-biopsy washing and post-biopsy washing cytology in the current study. Similar trend was noticed in previous studies also. [19],[22]

There has been a controversy as to whether bronchial washing should be routinely used or not. Many studies like Trevisani et al., [23] Karahalli et al. [17] in the past reported that the diagnostic yield did not increase significantly further by the addition of bronchial washing to bronchial biopsy and recommended that washing should not be routinely used. However, authors likes Mak et al., [12] Jones et al. [24] have suggested that bronchial biopsy, brushing and washing should be performed to obtain optimal diagnostic yield. Liwsrisakun et al. [25] have observed that the addition of bronchial washing to either biopsy or brushing is beneficial, but it may not be cost-effective.

False positive results were noticed in these cytological techniques used in the present study. It may be possible that some of these classified as false positives in the present study might be true positives as methods other than bronchial biopsy to confirm the diagnosis of lung cancer were not used in the present study. Majority of the previous studies [8],[9],[17],[19],[26] that have used other techniques such as rebronchoscopy, surgery, transthoracic needle aspiration (TTNA), tumor markers and autopsy, to prove the cases of lung cancer have shown that bronchial biopsy does not provide diagnostic yield in all cases of lung cancer. Chances of missing the diagnosis by bronchial biopsy are more in peripheral lung tumors. In the present study, most of false positive on brushing (8 out of 10) with respect to bronchial biopsy were diagnosed as adenocarcinoma. On bronchoscopic examination, the gross morphology of majority of these cases of adenocarcinoma were compression type lesion i.e., extrinsic compression of the bronchus by the lesion [15] and thus there may be a possibility of getting less representative material by bronchial biopsy in such tumors. Furthermore, in mucinous type of adenocarcinoma, bronchial biopsy specimen may contain pools of mucin, very few neoplastic cells with a relative lack of atypia that make the diagnosis of adenocarcinoma more difficult as observed by Butnor. [26]

One of the limitations of our study is use of only bronchial biopsy for the validation of cytological techniques and the absence of other confirmatory tests like surgical biopsy, transbronchial needle aspiration, TTNA, mediastinoscopy, biopsies of extrapulmonary lesions and autopsy. Other limitations was the inability to further typing of large cells carcinomas and sub-typing of poorly differentiated non-small cell carcinomas in the absence of tumor markers.

Based on findings of the study, it may be concluded that obtaining of bronchial brushing and washing cytology specimens using bronchoscopy in combination with imprint cytology aids in the diagnosis of lung tumors with a reasonable high accuracy rate of morphological typing of neoplasms. Therefore, all these techniques may be used concurrently along with bronchial biopsy to diagnose the lung tumors.

 
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Correspondence Address:
Anita Bodh
Department of Pathology, I.G.M.C., Shimla, Himachal Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0377-4929.118661

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