Journal of Cytology
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Year : 2019  |  Volume : 36  |  Issue : 3  |  Page : 157-159
Evaluation of imprint smears of bronchoscopic biopsy in lung tumors: A cytohistological correlation

Department of Pathology, IPGME and R, Kolkata, West Bengal, India

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Date of Web Publication18-Jun-2019


Background: There are several methods for obtaining samples in patients of lung tumors, of which bronchoscopic biopsy is the most common. In most of Indian scenario, however, histopathology diagnosis is time taking. Aims and Objectives: To evaluate imprint cytology as a tool for rapid diagnosis of lung carcinoma and its histopathological correlation. Study Type: Prospective study on accuracy of a diagnostic test. Materials and Methods: A total of 175 cases were included in the study, and all of them were subjected to brochoscopic biopsy. Imprint smears were prepared from all the bronchoscopy specimens obtained from 175 cases. Imprint smears were stained with Leishman-Giemsa cocktail and Pap stain, and histopathology sections were stained with hematoxlin and eosin. Histopathological findings were confirmed by immunohistochemistry. Results: Sensitivity and specificity of imprint cytology was 84.9% and 72.4%, respectively when compared to histopathology as standard. Conclusion: Imprint cytology can be used as a preliminary tool for diagnosis in lung tumor bronchoscopic biopsies.

Keywords: Bronchoscopic biopsy, imprint cytology, lung tumor

How to cite this article:
Chowdhury A. Evaluation of imprint smears of bronchoscopic biopsy in lung tumors: A cytohistological correlation. J Cytol 2019;36:157-9

How to cite this URL:
Chowdhury A. Evaluation of imprint smears of bronchoscopic biopsy in lung tumors: A cytohistological correlation. J Cytol [serial online] 2019 [cited 2023 Feb 7];36:157-9. Available from:

   Introduction Top

Lung cancer is currently the most frequently diagnosed cancer in the world and the most common cause of cancer-related mortality. The major risk factor for developing lung cancer is tobacco use. Over the coming decades, changes in smoking habits will greatly influence lung cancer incidence and mortality as well as the prevalence of various histologic types of lung cancer.[1]

Several methods are there for getting histopathological specimens. Among various bronchoscopic techniques, bronchial biopsy has the highest sensitivity for endobronchial malignant lesions.[2] However, as with any histopathology, it takes time to arrive at a diagnosis. Several researchers have emphasized about the role of imprint cytology in combination with histopathology to improve diagnostic accuracy and lessen reporting time to the patients. It can be used to give rapid, preliminary diagnosis of lung cancer.[3],[4],[5],[6],[7],[8],[9] Bronchial biopsy has also been used as the gold standard diagnostic test to assess the efficacy of other cytologic techniques.[10] Some studies in this topic are present worldwide, but there are only few studies in India, and to the best of our knowledge, none from our state or eastern India. Keeping these in mind, the current study was undertaken to assess the sensitivity and specificity of imprint smears of bronchial biopsy in diagnosing lung masses, histopathological diagnosis being taken as gold standard for confirmation.

   Materials and Methods Top

This study was a prospective one, conducted in the Department of Pathology and department of Pulmonology of a teaching institute, after prior approval from institutional ethics committee. The specimens for cytological and histological examination were collected from the indoor and outdoor patients of the Pulmonology Department in whom a provisional diagnosis of lung carcinoma was made according to clinical and radiological findings. A total of such 175 patients were included in the study. Patients who were not willing to undergo the procedure or were not medically fit for the procedure were excluded. The samples were obtained by flexible fiberoptic bronchoscopy done by the pulmonologist. Imprint smears were prepared from the bronchial biopsy in all the 175 cases. Imprint smears were prepared by placing forceps biopsy specimens on a glass slide by gentle touching and rolling over the surface. Care was taken to avoid crushing the specimen. Few of the smears were air dried and stained with Leishman-Giemsa (LG) cocktail stain. Others were fixed in absolute alcohol and stained with Pap stain. Bronchial biopsies were fixed in 10% neutral buffered formalin, and formalin fixed paraffin embedded sections were prepared, which were subsequently stained with hematoxylin and eosin (H and E). Cytology and histopathology slides were viewed independently by different pathologists. Immunohistochemical confirmation was done. Data were analyzed using Microsoft Excel (Microsoft Redmond, Washington, USA) and GraphPad Prism 5(GraphPad Prism softwares CA, USA).

   Results Top

The sensitivity and specificity of imprint smear were 84.9% and 72.4%, respectively. There were 22 false negative and eight false positive malignancy cases by imprint cytology [Table 1]. Seven cases of imprint cytology could not be categorized into specific cytologic subtype, however, malignancy was confirmed. These were categorized as “positive for malignancy.” Out of all 175 cases subjected to bronchoscopy, lung cancer was confirmed in 146 (83.4%) cases by histopathology of bronchial biopsy [Table 2]. Squamous cell carcinoma was found to be the most common lung cancer (40.4%) [Figure 1]a, followed by small cell carcinoma (31.5%) [Figure 1]b and adenocarcinoma (24.6%) [Figure 2]a. One case was diagnosed as small round cell tumor, which also correctly diagnosed by imprint cytology [Figure 2]b. Among patients diagnosed with lung cancer, 109 males (96.5%) and 12 females (36.4%) were active smokers or had a long history of smoking. The patients' age group ranged from 45 to 78 years, and the mean age was 62 years. Out of 175, 116 patients were from a rural background (66.3%).
Table 1: Results of imprint cytology compared to gold standard

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Table 2: Lung cancer distribution on final histopathological typing

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Figure 1: (a) Squamous cell carcinoma histopathology (Haematoxylin and eosin ×100). (b) Small cell carcinoma histopathology (Haematoxylin and eosin ×400)

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Figure 2: (a): Adenocarcinoma, imprint showing 3D clusters (Leishman Giemsa stain ×400). (b) Small round cell tumor imprint (Leishman Giemsa stain ×400)

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   Discussion Top

In the current study, we aimed at assessing the sensitivity and specificity of imprint smear cytology of bronchoscopic biopsy specimens in suspected cases of lung carcinoma. The imprint cytology results were compared to histopathological diagnosis, which was used as gold standard. Our study yielded a sensitivity of 84.9% and specificity of 72.4% for imprint smears. Out of the 120 cases detected correctly by imprint cytology as malignant cases, subtyping was done for 113 cases (94.1%), and seven cases were reported as “positive for malignancy.” The reason was observed to be scanty material and presence of obscuring blood and cell clumps.

Wolfgang et al. in 1991 studied the role of different techniques of diagnosis in bronchoscopic biopsy specimens.[5] The imprint of the forceps biopsy specimen yielded the highest number of positive results, and also there was agreement in the final morphologic tumor type in 136 of 158 cases (86.1%) by positive imprint cytology. Bodh et al. also found tumor typing good in imprint cytology.[11] They found that sensitivity and specificity of imprint smear were 81.35% and 78.12%, respectively and were higher than that of brushing. Tumor typing in their study was done in 69% cases. In our study, subcategorization into morphologic types was possible in 113 cases (94.1%). Our study results were in keeping with these studies, and correct morphological tumor typing was better in our study. This may be because of our use of Leishman-Giemsa cocktail stain and Pap stain for cytology, whereas Bodh et al. used Giemsa only.[12] According to the latest guidelines, tumor subcategory has been recommended in cytology also.[13] In studies by Jan et al., Paulose et al., Kawaraya et al., and Goyal et al., imprint cytology showed a high sensitivity, comparable to our study.[3],[4],[8],[9]

There were 8 false positive cases and 22 false negative cases in our study. False positive cases were most likely because of the abrasive artifacts produced during the imprinting process, which resulted in distorted cytomorphology. Similar problem was encountered by Wolfgang et al. as found in their study.[5] False negative cases might be due to the scanty tumor cells at the surface of specimen. Peritumoral inflammation and hemorrhage might have yielded less tumor cell on glass slides during imprinting. Some tumors such as mucinous adenocarcinoma and lepidic predominant adenocarcinoma have less atypical tumor cells and hence could have been missed oncytology.[13],[14]

The present study included only bronchoscopy as a modality to obtain biopsy samples. Previous studies also accessed other methods such as transthoracic needle aspiration, core biopsy for obtaining imprints. Peripherally located lesions could not have possibly been sampled as they usually do not produce endobronchial growths.[14]

   Conclusion Top

From the present study, it may be concluded that there is a definite role of imprint cytology in bronchoscopic biopsies in preliminary diagnosis of lung cancer, and it can be used over other cytologic methods with a better degree of accuracy. Tumor typing according to morphology is also an advantage in imprint cytology. Hence, use of imprint cytology in bronchoscopic biopsies of lung tumors is recommended for early and preliminary diagnosis.


All the teaching and technical staff of Pathology, IPGME & R Kolkata, all co-trainees.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Hussain AN. The Lung. In: Kumar, Abbas, Fausto, Aster, editors. Robbins & Cotran Pathologic basis of disease. 8th ed. PA, USA: Saunders Elsevier; 2010. p. 677-737.  Back to cited text no. 1
Schreiber G, McCrory DC. Performance characteristics of different modalities for diagnosis of suspected lung cancer: Summary of published evidence. Chest 2003;123:115S-28S.  Back to cited text no. 2
Paulose RR, Shee CD, Abdelhadi IA, Khan MK. Accuracy of touch imprint cytology in diagnosing lung cancer. Cytopathology 2004;15:109-12.  Back to cited text no. 3
Kawaraya M, Gemba K, Ueoka H, Nishii K, Kiura K, Kodani T, et al. Evaluation of various cytological examinations by bronchoscopy in the diagnosis of peripheral lung cancer. Br J Cancer 2003;89:1885-8.  Back to cited text no. 4
Wolfgang P, Rauscher H, Ritschka L, Susanne R, Hartmut Z, Werner D. Diagnostic sensitivity of different techniques in the diagnosis of lung tumors with the flexible fiberoptic bronchoscope: Comparison of brush biopsy, imprint cytology of forceps biopsy, and histology of forceps biopsy. Cancer 1991;67:72-5.  Back to cited text no. 5
Nishii K, Masashi K, Gemba K, Ueoka K, Kiura K, Kodani T, et al. Imprint cytology of biopsied samples and rinse fluid cytology of forceps and brush improve the diagnostic power of fiber optic bronchoscopy for peripheral lung cancer. J Clin Oncol 2004;22:7185-5.  Back to cited text no. 6
Staniszewski A, Marciniak M, Wachacka B, Ortowski TM. Intra operative imprint cytology in the diagnosis of lung tumours. Eur J Cancer1996;32(Suppl 1):S11.  Back to cited text no. 7
Jan RA. Yield of imprint and crush cytology in endo bronchial growths. Chest 2009;136:141S.  Back to cited text no. 8
Goyal S, Mohan H, Handa U, Saini V. Rinse fluid and imprint smear cytology of bronchial biopsies in diagnosis of lung tumors. Diagn Cytopathol 2012;40:98-103.  Back to cited text no. 9
Gaur DS, Thapliyal NC, Kishore S, Pathak VP. Efficacy of broncho-alveolar lavage and bronchial brush cytology in diagnosing lung cancers. J Cytol 2007;24:73-7.  Back to cited text no. 10
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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.  Back to cited text no. 11
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Sidhu SK, Ramalingam K, Goyal S, Poonia M, Rajawat GS, Sharma N. Comparing the efficacy of leishman–giemsa cocktail stain, giemsa stain, and Papanicolaou stain in potentially malignant oral lesions: A study on 540 cytological samples. J Cytol 2018;35:105-9.  Back to cited text no. 12
[PUBMED]  [Full text]  
Travis WD, Brambilla E, Noguchi M, Nicholson AG, Geisinger K, Yatabe Y, et al. Diagnosis of lung cancer in small biopsy and cytology. Arch Pathol Lab Med 2013;137:668-84.  Back to cited text no. 13
Butnor KJ. Avoiding underdiagnosis, overdiagnosis, and misdiagnosis of lung carcinoma. Arch Pathol Lab Med 2008;132:1118-32.  Back to cited text no. 14

Correspondence Address:
Dr. Abhishek Chowdhury
585/A/419/2, Kamalini Villa, DMS College Gate, Kaushallya, Kharagpur, Kolkata - 721 301, West Bengal
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/JOC.JOC_122_18

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