Cytopathology

Biography

Biography: Natália Coelho Couto de Azevedo Fernandes

Abstract

Liquid-based Cytology (LBC) consists of immediate fixation of cells in suspension with automated slide preparation. In this study, LBC with cell block (CB) immunocytochemistry was used to evaluate lymph node aspirates and results were compared with conventional cytology. The inter-rater reliability, unsatisfactory rate and accuracy between conventional cytology and LBC were assessed. Samples of enlarged lymph nodes were collected from 54 dogs through fine needle aspiration and fixed in preservative for LBC, CB and immunophenotyping. Two CB techniques were tested: fixed sediment method (FSM) with Bouin’s solution and agar method (AM). The morphology of the cells was blindly evaluated by 2 pathologists. Immunocytochemistry was performed with: Anti-CD79a, anti-Pax5, anti-CD3 and anti-Ki67. For inter-rater reliability, two veterinary pathologists classified the samples as POSITIVE, NEGATIVE or unsatisfactory for canine lymphoma, in a double-blind experiment. Results: of the 30 dogs, 80% had B cell lymphoma and 20%, T cell lymphoma. Considering conventional cytology, LBC smears showed better nuclear and nucleolar definition, but smaller cell size and worse cytoplasmic definition. FSM showed consistent cellular groups and were employed for immunocytochemistry, whereas AM presented sparse groups of lymphocytes that had been difficult to analyze. Anti-Pax-5 allowed identification of B cells. LBC inter-rater reliability was good (k=0.762). LBC with CB immunocytochemistry presented an accuracy of 89.47% compared to 68.42% from conventional cytology. Moreover, the unsatisfactory rate was reduced from 11.76% (conventional) to 3.71% (LBC + CB Immunocytochemistry). LBC and FSM, together, may be promising tools to improve canine lymphoma diagnosis through fine-needle aspiration.