Portal de Pesquisa da BVS Veterinária

Acta sci. vet. (Impr.); 40(1): Pub. 1025, 2012. ilus

Artigo em Inglês | VETINDEX | ID: biblio-1373546

Resumo

Background: Carcinosarcoma of the breast (metaplastic, biphasic metaplastic, metaplastic sarcomatoid carcinoma, sarcomatoid carcinoma) is an aggressive, rare neoplasm that has been reported to account for 0.08-0.2% of all breast malignancies. Mammary carcinosarcoma is rare in rabbits. Carcinosarcoma is a neoplasia composed of cells morphologically resembling malignant epithelial components and cells resembling malignant connective tissue elements. In spite of the rarity in rabbits, carcinosarcoma should always be considered in the different diagnoses of the mammary neoplasias, especially those of undifferentiated neoplasias. Case: An eight-month-old, female New Zealand white rabbit (Oryctolagus cuniculus) weighing 1.9 kg was referred to Tabriz university veterinary hospital for acute swelling on the abdomen and history of mammary mass. The complete blood count was within the reference ranges. The rabbit had been slightly depressed and anorectic. At clinical examination, the patient presented a huge lobulated mass in the mammary gland area. Clinical signs were included: emaciation and hardness in moving. Due to unfavorable prognosis the rabbit was euthanized and afterward complete mastectomy was performed. At necropsy, a non-infiltrative multilobulated mass were observed in the chirurgic area. The mass didn't infiltrate into the skin, subcutaneously and adjacent to the musculature and it was moved easily. The neoplasia was solid, firm, and yellowbrownish. Tissue samples of the tumor were fixed in 10% neutral buffered formalin, embedded in paraffin, cut at 5 µm, and stained with hematoxylin and eosin and masson trichrome. Microscopically, the neoplasm had a solid pattern and was composed of a heterogeneous cell population, mainly pleomorphics. Polyhedral cells showing ovoid or vesicular nuclei with prominent nucleoli and abundant lightly acidophilic cytoplasm resembling epithelial cells were observed. Cells with scant cytoplasm and elongated or oval nuclei containing inconspicuous nucleoli resembling mesenchymal cell were also observed. There were also neoplastic areas with a myxoide matrix. Some young cartilage pieces were observed in the tumor. In some parts of the tumor a very dense fibrous connective tissue was observed. Based on the histological findings, the diagnosis of mammary carcinosarcoma was confirmed. Other organs showed normal histological characteristics. Discussion: The carcinosarcoma is a neoplasia characterized as containing a mixed cell population with malignant proliferation of both mesenchymal and epithelial-like cells. Although the carcinosarcoma is rare in the domestic species, their origin has been discussed in two theories: 1) multiclonal theory suggests that the epithelial and the mesenchymal components originated from two or more stem cells; 2) the monoclonal theory suggests that the epithelial and the mesenchymal components originated from totipotential neoplastic cells play multiple potential pathways of terminal differentiation. Abnormal level of growth and Prolactin hormones is one cause to breast tumors. Recent evidence supports the speculation that prolonged hyperprolactinemia leads to malignancy, given the case of ductal carcinoma in one woman who, after incomplete pituitary adenomectomy, was hyperprolactinemic for 15 years. This physiologic relationship and disease progression are important to consider in clinical diagnosis and management of these cases in rabbits. Although some studies were not showed any difference in level of mentioned hormones. In spite of being rare in rabbit, the carcinosarcoma should always be considered in the different diagnoses of the mammary neoplasias, mainly of those undifferentiated neoplasias.

Biblioteca responsável: BR68.1