The diagnostic utility of squash smear cytology in lung malignancies

Abstract

BackgroundLung malignancy is the most common cause of death worldwide. The main role of pathologist is to differentiate small cell from other cell types as treatment and prognosis varies. Although histopathology is routinely done, squash smears yield better cytomorphology.Aims and objectivesTo study the clinical history, evaluate the diagnostic yield by means of cytology and histopathology correlation followed by determination of sensitivity and specificity of squash smear cytology for detection of lung malignancies.Materials and methodsThe present study was an observational analytical study conducted over a period of 3.5 years. Total 60 squash smears were obtained by computed tomography-/bronchoscopy-guided biopsy and stained with Papanicolaou and May-Grunwald stain. Squash smears were correlated with histopathological findings.Statistical analysisStatistics in the form of sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio were done.ResultsOut of total 60 cases, 71.67% cases were males and 65% cases were smokers. Right lung was mostly involved (65%). The major symptom noted was dyspnea on exertion (90%). In 66.7% cases, malignancy was reported while in 10% suspicious and in 23.3% negative for malignancy. The most common malignancy diagnosed was squamous cell carcinoma (18.3%). The sensitivity and specificity of 92.1% and 83.3% were calculated respectively for squash smear, while the positive predictive value (PPV) was 94.6% and the negative predictive value (NPV) was 76.9%.ConclusionSquash smear cytology utilization in diagnosis of lung malignancy is a simple, fast, and reliable procedure with good sensitivity and specificity. It can be used as complementary to histopathology when need arises.