Diagnostic Accuracy of Cell Block versus Conventional Cytological Smear in Malignant Pleural Effusion: A Comparative Study

Abstract

Background: Malignant pleural effusion (MPE) is a common oncological complication that requires accurate diagnosis to guide appropriate management. Cytological smears are widely used; however, they have variable sensitivity. The cell block technique has emerged as a potentially superior diagnostic tool due to its better preservation of cellular architecture and compatibility with ancillary testing.

Objective: This study aims to compare the diagnostic utility of the cell block technique with the conventional cytological smear in detecting MPE, using histopathology as the gold standard.

Methods: This cross-sectional study was conducted at the Institute of Tuberculosis and Chest Medicine, Mayo Hospital, Lahore. One hundred and thirty-eight patients, aged 18 to 75 years, with probable malignant pleural effusion were enrolled. Pleural fluid specimens were subjected to both conventional cytology and cell block analysis. All patients subsequently received a pleural biopsy for histological validation. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were calculated using SPSS version 27.0.

Results Cytology demonstrated a sensitivity of 65.82%, specificity of 86.44%, PPV of 86.67%, NPV of 65.38%, and overall diagnostic accuracy of 74.64%. The cell block technique demonstrated a significantly higher sensitivity (89.87%), specificity (94.92%), PPV (95.95%), NPV (87.50%), and overall diagnostic accuracy (92.03%) (p =0.002).

Conclusion: The cell block technique is more effective than conventional cytological smears in diagnosing malignant pleural effusion, offering higher sensitivity, specificity, and diagnostic accuracy.