A comparative study between cytology and histopathology of various neoplasms from 150 dogs was carried out. Several staining methods including Wright, May-Grünwald-Giemsa, New-Methylene Blue and Papanicolau, and histological staining methods such as Hematoxilin & Eosin, van Gieson, Sudan, Toluidine Blue and Periodic Acid Schiff were used. The data obtained indicated an 85.3% accuracy for the cytological diagnosis when the histopathological diagnosis was considered as the correct parameter. In 4.0% of the cases only the embrionary origin of the neoplasms was determined, and in 1.3% only the prognosis was established. The cytological diagnosis differed from the histopathological diagnosis in 8.1% of the cases. In two cases (1.3%), although the cytological and histopathological diagnoses differed, a reexamination determined that the former was correct which increased its accuracy up to 86.6%. Fine needle aspiration biopsy proved to be the best technique to obtain samples for the study. Cytology was found not suitable for the diagnosis of mammary neoplasms due to the wide variation of the cytological aspects from different areas. The imprint on slides is a technique not recommended to evaluate mesenchymal tumors and should be replaced by exfoliative cytology. The Wright method proved to be the more efficient staining method. Adapted staining methods from histopathology such as van Gieson for leiomyomas and leiomyosarcomas, Sudan Black B for lipomas and liposarcomas, and Periodic Acid of Schiff and Toluidine Blue for mastocytomas, were especially useful in visualizing the fine morphological details of various epithelial and mesenchymal neoplasms examined.
Cytology; histopathology; staining; diagnosis; neoplasms
