Revista de citología e histología

Spontaneous Osteosarcoma in Dogs: Diagnosis through Cytopathological and Histopathological Assays

Abstract

Marcela da Costa Gomes and Noeme Sousa Rocha

Background: Appendicular osteosarcoma is the main primary malignant and non-hematopoietic bone tumor in dogs. It appears spontaneously in the appendicular skeleton with a relevant incidence both in dogs and in human children. Unfortunately, it is an aggressive neoplasm with high rates of metastasis regardless of the species and that afflicts, among other organs, the lungs. The high rate of lethality is due to the terrible survival prognosis for patients with lung metastasis and due to chemotherapy. Traditionally, amputation is the therapeutic indication, followed by chemotherapy. For human patients, the chemotherapeutic treatment, based on a prior anatomopathological diagnosis referencing even the degree of aggressiveness, results in a better rate of survival as it reduces metastases. However, this approach is not often explored in veterinary medicine, which features amputation as the traditional approach, followed by chemotherapy.
Objective: Verify the morphological expression of the parameters used in the cytopathological diagnosis through fine needle aspiration cytology of spontaneous osteosarcomas in dogs from varying breeds, including mixedbreeds. The study also aims the analysis of possible concordances between cytopathological and histopathological parameters in osteosarcomas.
Methods: This study verified, through optical microscopy, the morphological expression of parameters used in the cytopathological diagnosis of osteosarcomas in twenty dogs of different breeds, including mixed-breeds, and then conducted an analysis of possible concordances between these parameters. The cytological assay was conducted through fine needle aspiration cytology, using Giemsa and Papanicolaou stain on the microscope slides. The histopathological assay was conducted through the use of biopsies of surgical specimens, which were processed according to the standard procedures and stained with hematoxylin-eosin. The tumors were classified based on the guidelines proposed by the World Health Organization.
Results: There were malignancy criteria significantly repeated both at cytopathological and at histopathological assays.
Conclusion: These findings show us that the cytopathological assay through aspiration may be used as a trustworthy diagnostic method for osteosarcomas in dogs.