Caracterização histopatológica e imunoistoquímica de neoplasmas mamários espontâneos de gatas (Felis catus)

Abstract

After skin tumors and lymphohematopoietic tissue, mammary neoplasms are most common in domestic cats. Mammary carcinomas of cats have poor prognosis, since such tumors are very aggressive and with great ability to generate metastases. The aim of this study was to characterize the point of view histopathological, histochemical and immunohistochemical, spontaneously occurring mammary tumors in cats. Thirty-five samples of tumor tissue were collected surgically and histological sections were stained with hematoxylin-eosin (HE) for histopathological analysis. For histochemical analysis, were used the Masson’s Trichrome and Periodic Acid Schiff (PAS) to evaluate the deposition of collagen and glycosaminoglycans associated with tumors, respectively. To perform the immunohistochemistry assays were used anti-Ki-67, anti-PCNA and anti-Bcl-2. The obtained results showed that 14.29% of the lesions were classified as benign (fibroadenoma, adenoma and simple adenosis) and 85.71% as adenocarcinomas. Malignant neoplasms were multifocal, predominantly of invasive growth pattern, presence of necrosis, mitotic figures, and inflammatory infiltrate. The histochemical analysis revealed that the malignant lesions exhibited moderate to strong staining pattern when stained with PAS and weak to moderate with MT. Marking anti-Ki-67 showed cytoplasmic and nuclear pattern in well-differentiated malignant cells in tumor tissue. The protein Bcl-2 showed membrane pattern restricted to the processed tissue and the tissue marked with anti-PCNA showed nuclear and cytoplasmic pattern in glandular cells, occasionally in stromal cells of epithelioid appearance. In summary, the large number of mitotic figures and increased reactivity to staining with anti-PCNA antibody suggests neoplasms with intense proliferative activity indicating a poor prognosis for affected individuals.