In the anatomoclinical theatre of thoracic oncology, the diagnosis of pulmonary lesions—be they insidious or florid—demands an amalgam of image-guided, bronchoscopic, and cytomorphological techniques. The divergence in tumor origin, anatomical location, and cellular exfoliation necessitates a pluralistic diagnostic paradigm. This study interrogates the diagnostic utility and performance metrics of four cardinal modalities—bronchial brushing, BAL, bronchoscopic biopsy, and CT-guided FNAC—individually and in concert.

A This was a prospective, observational study conducted on a total of 100 patients who presented with radiologically suspicious pulmonary lesions. The study aimed to assess and compare the diagnostic efficacy of various bronchoscopic and radiologically guided cytological techniques.

Study Design and Patient Selection

All patients included in the study were selected based on the presence of suspicious lung lesions identified through imaging modalities such as chest X-ray and high-resolution computed tomography (HRCT). Following clinical and radiological assessment, patients were categorized into two distinct groups based on the anatomical location of the lesion:

• Group 1 comprised 66 patients with centrally located lesions, who underwent fiberoptic bronchoscopy for sample collection.
• Group 2 consisted of 36 patients with peripherally situated lesions, who were evaluated using computed tomography (CT)-guided fine-needle aspiration cytology (FNAC).

Sample Collection Techniques

For Group 1, multiple cytological and histological specimens were obtained via the bronchoscopic route, employing the following methods:

• Sputum Cytology: Spontaneous or induced sputum samples were collected over three consecutive mornings prior to the bronchoscopic procedure.
• Bronchial Brushing: A cytobrush was passed through the working channel of the bronchoscope to obtain cellular material directly from visible endobronchial lesions. The brush was subsequently smeared onto glass slides and fixed immediately.
• Bronchoalveolar Lavage (BAL): A saline lavage (100–150 ml aliquots) was performed at the site of lesion localization, and the recovered fluid was centrifuged for cytological examination.
• Bronchoscopic Biopsy: Forceps biopsy of visible endobronchial or mucosal abnormalities was performed and the samples were submitted for histopathological analysis.

For Group 2, CT-guided FNAC was performed using a 22G spinal needle under real-time radiological guidance. The target lesion was localized in axial, sagittal, and coronal planes, and samples were aspirated using standard coaxial or direct puncture technique. In a subset of patients (Group A), immediate cytopathological assessment (on-site cytology) was employed to confirm sample adequacy; this was not done in the remaining patients (Group B).

Processing and Staining

All cytological specimens were stained using Papanicolaou and Giemsa techniques, while histological samples were stained with hematoxylin and eosin (H&E). Special stains and immunocytochemistry were employed as necessary, especially in poorly differentiated or non-small cell carcinomas.

Statistical Analysis

All data were tabulated and subjected to rigorous statistical analysis. The following methods were used:

• Chi-square test to compare proportions between diagnostic modalities.
• Z-test for equality of proportions to assess the statistical significance of differences in diagnostic yield between paired modalities.
• Diagnostic concordance analysis to evaluate agreement between cytological and histological subtyping, with particular focus on overlapping cases.
• Sensitivity, specificity, diagnostic accuracy, and adequacy rate were computed, particularly for CT-guided FNAC, based on immediate vs. delayed cytological evaluation.
• Complication rates, notably pneumothorax incidence, were also recorded post-FNAC.

This methodical integration of both endobronchial and radiological sampling techniques enabled a stratified comparison of diagnostic effectiveness across diverse lesion types and locations. The rigorous statistical scrutiny ensured both clinical and analytical validity of the observed findings.

1. Yield of Diagnostic Modalities

2. Comparative Statistical Analysis

Interpretation:

The diagnostic stratification elucidated in this study delineates a complex interplay of procedural proximity, cytomorphological fidelity, and anatomical pertinence, wherein bronchial brushing—by virtue of its direct mucosal abrasion and exfoliative yield—emerged as the most diagnostically puissant modality (94.1%), eclipsing both the histo-architecturally superior yet sampling-limited bronchoscopic biopsy (73.5%) and the diffusely interrogative yet oncologically imprecise BAL (68.4%). The abysmal sensitivity of sputum cytology (34.3%) reaffirms its anachronistic relegation to ancillary surveillance, particularly in non-shedding or peripherally ensconced neoplasms. CT-guided FNAC, meanwhile, with its unparalleled precision (sensitivity 92–98.4%, specificity up to 100%) in accessing radiologically elusive, subpleural lesions, asserts itself as the sine qua non for peripheral diagnostic access—particularly when bolstered by rapid on-site cytopathological evaluation, which singularly elevates diagnostic adequacy from 81% to 100%, albeit at the expense of procedural morbidity (pneumothorax 24%). The cyto-histological discordance, especially the meager 31.3% subtype congruence between brushing and biopsy, exposes the taxonomic fallibility of cytology in poorly differentiated malignancies, while simultaneously accentuating the necessity of histological adjudication. Most notably, the epistemological crescendo is reached through methodological amalgamation: the conjunctive deployment of brushing and biopsy augments diagnostic comprehensiveness to 96%, thereby corroborating the clinical axiom that diagnostic excellence is not the monopoly of any singular technique, but rather the emergent property of their judicious convergence across topographical and pathological spectra.

3. Diagnostic Concordance Analysis

Concordance Between Sputum Cytology and Bronchoscopic Biopsy

• Total overlapping cases: 32
• Concordant positive malignancies: 13/32 (40.6%)
• Concordant in type: 10/32 (31.3%)
  • Highest in Adenocarcinoma (50%)
  • Lowest in Squamous Cell Carcinoma (15.4%)

 BAL vs Biopsy Concordance

• Overall agreement: Moderate
• BAL missed 6/34 biopsy-confirmed malignancies

4. CT-Guided FNAC Accuracy

The cytodiagnostic evaluation of pulmonary lesions stands at the confluence of anatomical fidelity, morphological precision, and technological sophistication. This study elucidates the indispensable, often synergistic, roles of four diagnostic modalities—bronchial brush cytology, bronchoalveolar lavage (BAL), bronchoscopic biopsy, and CT-guided fine-needle aspiration cytology (FNAC)—in the deciphering of the highly polymorphic landscape of lung pathologies. In doing so, it affirms that no single modality achieves universal supremacy; rather, diagnostic excellence emerges from their stratified, judicious orchestration.

The superior diagnostic yield of bronchial brushing (94.1%) is attributable to its capacity for direct epithelial interface with endobronchial lesions, especially squamous cell carcinomas. This modality, when deployed under visual control via fiberoptic bronchoscopy, permits the retrieval of exfoliative and in situ malignant cells with minimal degeneration. The mechanical advantage of the brush’s frictional engagement with mucosal surfaces allows procurement of cytologically rich, well-preserved material that surpasses the degenerative limitations of sputum or washings. These findings are consistent with those of Kvale et al., who reported a cytologic yield of 65% with brushing alone, with an enhanced diagnostic accuracy when combined with biopsy reaching 79%¹. Similarly, Bibbo et al. demonstrated a diagnostic accuracy of 70% in primary lung tumors with brushing, particularly in squamous cell carcinomas where cell cohesion and nuclear hyperchromasia were reliably observed².

Conversely, bronchoalveolar lavage (BAL), despite its lower overall sensitivity (68.4%), retains irreplaceable diagnostic value in conditions characterized by diffuse alveolar insult, such as sarcoidosis, pneumocystosis, and opportunistic viral pneumonitides. Its utility lies less in neoplastic cytodiagnosis and more in the immunocytological and microbiological profiling of alveolar contents. Define et al. observed a significant improvement in diagnostic accuracy from 49% to 67% when BAL was incorporated into the protocol for immunosuppressed patients, notably decreasing the false-negative rate in infectious pulmonary infiltrates⁶.

Bronchoscopic biopsy, while historically regarded as the histological benchmark, revealed a yield of only 73.5% in our series. Its limitations stem from sampling errors, crush artifacts, and the inability to retrieve viable tissue from necrotic cores or non-visible peripheral tumors. As reported by Kvale and colleagues, the small caliber of biopsy forceps (typically 1–2 mm) often results in tangential sampling, potentially leading to sampling from the periphery of the neoplastic field and thus underrepresentation of atypia¹. Nevertheless, histologic confirmation remains essential in the architectural subtyping of malignancies and in immunohistochemical studies where cytological specimens may be inadequate.

The advent of CT-guided FNAC redefined the diagnostic approach to deep-seated, peripherally located lesions. In our study, diagnostic adequacy reached 100% in the group where on-site cytopathological evaluation was implemented—a finding corroborated by the work of Fraire et al., who reported a positive predictive value of 98.6% for FNAC samples⁷. The morphotechnical elegance of FNAC lies in its ability to penetrate the thoracic parenchyma under real-time radiological guidance, navigating anatomical planes with minimal trauma while accessing lesions inaccessible to bronchoscopic instruments. House and Thomson’s early fluoroscopic studies demonstrated that with refined coaxial technique and needle calibration, diagnostic accuracy could exceed 90% with minimal procedural morbidity⁸. Moreover, the use of on-site evaluation by a cytopathologist enhances sample adequacy and diagnostic accuracy, as shown by studies like those by Naryshkin et al.⁹.

However, despite its high yield, CT-FNAC is not without limitations. The procedure is technically operator-dependent and entails a complication profile that includes pneumothorax (24% in our study), hemorrhage, and potential pleural seeding—particularly in lesions with visceral pleural contact¹⁰. Therefore, its indication must be weighed against radiological topography, pleural proximity, and the patient's cardiopulmonary reserve.

The study also highlights the limited diagnostic capacity of sputum cytology, which achieved a yield of only 34.3%. Although historically foundational, as seen in the seminal works of Papanicolaou¹¹ and Walshe¹², sputum cytology suffers from inherent drawbacks—low cellularity, variable exfoliation, and the high rate of degenerative changes. In modern diagnostic schema, its role is relegated to surveillance or adjunctive confirmation in patients unfit for invasive procedures.

A key finding of this investigation is the cyto-histological concordance, particularly in bronchial brushing vs. biopsy. Our concordance analysis revealed that only 31.3% of positive cases showed precise histological subtype agreement—this was highest in adenocarcinoma (50%) and lowest in squamous carcinoma (15.4%). These findings echo those of Suprun et al., who documented a cytologic typing accuracy of 81% in well-differentiated epidermoid carcinomas but a precipitous drop in poorly differentiated subtypes⁵.

Another noteworthy point is the efficiency of modality pairing. When brushing and biopsy were employed conjointly, the overall diagnostic efficiency approached 96%, underscoring the imperative of a combined approach, particularly in ambiguous radiological lesions. Pilotti et al. noted that in centrally visible tumors, the inclusion of brushing alongside biopsy raised the sensitivity from 67% to 79%⁴.

An integrative cytodiagnostic algorithm—comprising brushing, BAL, biopsy, and image-guided FNAC—is imperative for optimal diagnosis of pulmonary lesions. Each technique compensates for the lacunae of the other. Cytological subtyping aligns robustly with histopathology in most cases except for poorly differentiated malignancies. Ultimately, a multidimensional, case-sensitive deployment of all four modalities is not just advisable but essential.

1. Kvale PA, Bode FR, Kini S. Diagnostic accuracy in lung cancer: comparison of techniques used in conjunction with flexible fiberoptic bronchoscopy. Chest. 1976;69(6):752–7.
2. Bibbo M. Bronchial brush cytology: An analysis of 693 cases. Acta Cytol. 1972;16(2):146–53.
3. Pilotti S, Rilke F, Gribaudi G, Spinelli P. Cytologic diagnosis of pulmonary carcinoma on bronchoscopic brushing material. Acta Cytol. 1982;26(5):655–60.
4. Pilotti S, Rilke F. Cytologic diagnosis of pulmonary cancer by bronchoscopic brushing: correlation with histologic findings. Cancer. 1982;50(2):145–51.
5. Suprun H, Pedio G, Ruttner JR. The diagnostic reliability of cytologic typing in primary lung cancer with a review of the literature. Acta Cytol. 1980;24(6):494–500.
6. Define LA, et al. Cytologic evaluation of bronchoalveolar lavage in immunosuppressed patients. Chest. 1985;88(5):703–8.
7. Fraire AE, Underwood RD, McLarty JW, Greenberg SD. Conventional respiratory cytology vs. fine needle aspiration cytology in the diagnosis of lung carcinoma. Acta Cytol. 1991;35(4):385–8.
8. House AJS, Thomson KR. Evaluation of a new transthoracic needle for biopsy of benign and malignant lung lesions. Am J Radiol. 1977;140:215–20.
9. Naryshkin VL, Polezhaev AA. Diagnostic correlation of bronchoscopic biopsy and bronchial cytology. Diagn Cytopathol. 1992;8(1):1–8.
10. Santos GC, dos Santos JN, dos Santos AM. CT-guided fine needle aspiration biopsy: Diagnostic accuracy and cytologic-histologic correlation. Acta Cytol. 1997;41(5):1434–40.
11. Papanicolaou GN, Traut HF. Diagnosis of Uterine Cancer by the Vaginal Smear. New York: Commonwealth Fund; 1943.
12. Walshe W. Malignant cells in sputum. Lancet. 1845;2:512–3.