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Acta sci. vet. (Impr.); 40(2): Pub. 1042, 2012. ilus

Artigo em Português | VETINDEX | ID: biblio-1373567

Resumo

Background: Chondrosarcoma is a malignant neoplasm originated from chondroid cells with production of cartilage matrix with lot of degrees of differentiation. It may be found in skeletal or extraskeletal tissue, more commonly in flat bones. It most often has an aggressive behavior with involvement of bone and adjacent soft tissues, which necessitates their rapid identification, surgical intervention and therapy. Chondrosarcoma is reported as uncommon neoplasm in the nasal cavity of dogs and should be distinguished by both other malignancies and for non-neoplastic diseases. Case: A 7-years-old dog, mixed breed, male, had a swelling in the nasal cavity for more than 30 days. The change was seen in the right frontal-nasal region with invasion of the oral cavity, with serous nasal discharge and also, inspiratory and expiratory noises. Even after cytology and biopsy of the tumor to chemotherapy instituted, there was not successful and the dog was euthanized. At necropsy, there was a large multilobulated mass, with firm consistency, interspersed with soft areas in the right nasal region. In the cut surface, the mass showed staining grayish-white interspersed with dark areas, which block most of the nasal cavity causing partial lysis of frontal, temporal and tubinates bones, as well as purulent secretion of the frontal sinuses (sinusitis). Microscopically, the mass consisted of mesenchymal neoplastic cells arranged in bundles or nodules without orientation, separated by fine bands of fibrous connective tissue poorly vascularized. The neoplastic cells showed round to oval nucleus, sparse chromatin and conspicuous nucleoli. Some areas were more solid and composed of cells with few cytoplasm, similar to chondroblastic cells. It was observed multifocal areas of chondroid matrix formation. Discussion: Based on pathological findings, the diagnosis of chondrosarcoma was confirmed. The histopathological findings confirmed the diagnosis of chondrosarcoma suggested by cytology. Despite being an uncommon neoplasm in dogs, chondrosarcoma should be considered as differential diagnosis of other nasal diseases that can lead macroscopic changes and similar clinical signs. The osteosarcoma is the most common bone tumor of the nasal cavity in dogs. The similarity of the macroscopic findings of chondrosarcoma and oesteosarcoma, as well as histological and immunohistochemical stain, may be a challenge to diagnosis for the clinician and pathologist. Other neoplasms such as squamous cell carcinoma, fibrosarcoma and hemangiosarcoma, as well as proliferative rhinitis caused by fungal agents, should also be considered in the differential diagnosis. These conditions can be differentiated by microscopic features and immunohistochemical stain. The fine needle aspiration biopsy is an important method, however to establish the definitive diagnosis is always required histopathologic evaluation. In primary chondrosarcoma of the nasal cavity in dogs, the survival with treatment is made from three to six months, however, often results in local severe invasion and serious clinical changes. In this case, the treatment was not effective because the degree of tumor differentiation and infiltration of the surrounding structures, as well as worsens of the clinical signs. The knowledge of the clinicopathological findings and biology of this tumor is essential for rapid diagnosis and more effective clinical interventions.

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