Role of Cell Block Technique by Fixed Sediment Method in Fluid Cytology - Abstract
Cytological examination of serous effusions is of paramount importance in the diagnostic algorithm and has therapeutic as well as prognostic implications. Reactive mesothelial cells, abundance of inflammatory cells and paucity of representative cells contribute to considerable difficulties in making conclusive diagnosis on conventional
Centrifuged smears (CS) especially in recognition of malignant effusions. The cell block (CB) technique of examining fluids along with concomitant use of smears has shown an added advantage in study of effusions, where the residual material can be evaluated in a simple, expedient fashion by paraffin embedding.
Aim: To study the efficacy of CS vs. CB by fixed sediment method (FSM) in effusions (pleural, peritoneal, pericardial, synovial), CSF and Broncho alveolar lavage (BAL).
Materials and methods: A total of 170 fluids (pleural, peritoneal, pericardial, CSF, BAL and synovial) received in the cytology section of a tertiary care hospital in south India, were included in the study. The fluids were examined grossly and were divided into two equal parts. One part was used for CS and the other part for CB by FSM of Nathan et al. Role of volume and degree of pellet formation was also studied. Comparison of CS and CB was studied by Chi-square test and kappa test. A p value of < 0.05 was considered significant.
Results: Majority (57%) of the fluids were exudates from pleural cavities. Males predominating, the peak age was between 40-70years. CB gave an improved diagnosis in 75% of malignant cases, both in pleural and peritoneal effusions compared to 25.7% and 18.9% of benign cases respectively. Among the CB of BAL fluids, 16 cases were non-diagnostic & 4 cases confirmed the diagnosis given on CS. CSF samples were 7 in number, out of which none of them yielded material on CB. CB confirmed the diagnosis in 50% of pericardial effusions. Statistical analysis by Chi-square test showed a p value of 0.000264. Kappa test showed fair degree of agreement between CS and CB (kappa value = 0.2119).
Conclusions: CB preparation by FSM is an easy, simple yet reliable and cost-effective method, which can be incorporated into routine cytology laboratory. CBs were complementary to CS in the overall categorization of benign and malignant groups. CBs appeared to be more useful in diagnosis of malignancy by a good pellet formation, preserved architectural patterns, thereby bridging cytology and histopathology.