CELL BLOCKS OF CANINE AND FELINE EFFUSION

ABSTRACT Valentina Crippa Cell Blocks from canine and feline effusions Objective: To evaluate the sensitivity and specificity of a panel of markers in distinguishing mesothelial cells from metastatic adenocarcinoma cells in Cell blocks from canine and feline effusion. Methods: This study included 28 effusion specimens from dogs and cats with a cytological diagnosis of reactive effusion or malignancy of non-hematopoietic origin. Cell Blocks were stained with a standard panel of Vimentin, panCK (MNF116), CK 5/6 and HBME-1 as mesothelial cell markers; Desmin as marker of benign mesothelial cells; Claudin 4 as epithelial marker and CK7/CK20 as a marker of metastasis. Malignancy was confirmed by histologic evaluation; non-malignant conditions were confirmed by histopathology or follow up. Sensitivities, specificities, predictive values and accuracy were calculated. Results: CK5/6 demonstrated a high specificity (100%) for mesothelium. For the detection of canine and feline mesothelial cells the coexpression of panCK and VIM displayed the best sensibility (94,1%) while HBME-1 was the antibody that presented highest accuracy. Claudin 4 demonstrated a very low sensibility versus canine and feline epithelial cells. Conclusion: The most specific marker, with for the identification of mesothelial cells in canine and effusion, is the Vim/CK coexpression, being CK5/6 the most specific and HBME-1 the marker with the highest overall accuracy. Desmin is a useful marker in discriminating between benign and malignant mesothelial cells. The coordinate expression of CK7/CK20+ has not proved to be useful on the identification of metastatic cells on effusion. The study of Claudin 4 necessitate to be deepened in veterinary medicine. In conclusion, the combination of both cytology and immunohistochemistry studies can greatly enhance the diagnostic accuracy, sensitivity and specificity in malignant effusions.